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Journal articles on the topic 'Thiol binding'

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Author: Grafiati
Published: 4 June 2021
Last updated: 20 February 2023

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1

Lee, Duk-Shin, and Ji-Eun Kim. "PDI-Mediated Reduction of Disulfide Bond on PSD95 Increases Spontaneous Seizure Activity by Regulating NR2A–PSD95 Interaction in Epileptic Rats Independent of S-Nitrosylation." International Journal of Molecular Sciences 21, no. 6 (March 18, 2020): 2094. http://dx.doi.org/10.3390/ijms21062094.

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Postsynaptic density-95 (PSD95), a major scaffolding protein, is critical in coupling N-methyl-D-aspartate receptor (NMDAR) to cellular signaling networks in the central nervous system. A couple of cysteine residues in the N-terminus of PSD95 are potential sites for disulfide bonding, S-nitrosylation and/or palmitoylation. Protein disulfide isomerase (PDI) reduces disulfide bonds (S-S) to free thiol (-SH) on various proteins. However, the involvement of PDI in disulfide bond formation/S-nitrosylation of PSD95 and its role in epilepsy are still unknown. In the present study, acute seizure activity significantly increased the bindings of PDI to NR2A, but not to PSD95, while it decreased the NR2A–PSD95 binding. In addition, pilocarpine-induced seizures increased the amount of nitrosylated (SNO-) thiols, not total (free and SNO-) thiols, on PSD95. Unlike acute seizure, spontaneous seizing rats showed the increases in PDI–PSD95 binding, total- and SNO-thiol levels on PSD95, and NR2A–PSD95 interaction. PDI siRNA effectively reduced spontaneous seizure activity with decreases in total thiol level on PSD95 and NR2A–PSD95 association. These findings indicate that PDI-mediated reduction of disulfide-bond formations may facilitate the NR2A–PSD95 binding and contribute to spontaneous seizure generation in epileptic animals.
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2

QUINLAN, Gregory J., Michael P. MARGARSON, Sharon MUMBY, Timothy W. EVANS, and John M. C. GUTTERIDGE. "Administration of albumin to patients with sepsis syndrome: a possible beneficial role in plasma thiol repletion." Clinical Science 95, no. 4 (October 1, 1998): 459–65. http://dx.doi.org/10.1042/cs0950459.

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1.Albumin is often administered intravenously to critically ill patients as a volume expander, to combat hypoalbuminaemia, and to decrease hyperbilirubinaemia. There is, however, an ongoing debate concerning the therapeutic benefit of the former which is an expensive form of treatment. 2.Albumin has several biological functions, in particular as a ligand binder. It also acts as an extracellular transition metal ion-binding and radical-scavenging antioxidant. These functions are influenced by the presence of an exposed thiol group (cys 34) on the surface of the albumin molecule. 3.The ability of infused albumin to influence the plasma thiol pool, and hence antioxidant potential, was investigated in patients with sepsis syndrome. 4.Plasma thiol levels rose rapidly after albumin infusion and remained elevated even after plasma albumin levels had declined significantly, due to interstitial leakage. Data are suggestive of some form of thiol exchange in the plasma of these patients between albumin and molecules containing oxidized thiol groups. 5.Administration of albumin to patients with sepsis syndrome leads to a sustained increase in plasma thiols. Thiols have several important antioxidant functions, and thiol repletion in these patients, who are known to suffer from oxidative stress, may have beneficial antioxidant effects. Antioxidant repletion may represent an important facet of clinically administered albumin.
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3

Choi, Hiuwan, Khatira Aboulfatova, Henry J. Pownall, Richard Cook, and Jing-fei Dong. "Shear-induced Disulfide Bond Formation Regulates Adhesion Activity of von Willebrand Factor." Journal of Biological Chemistry 282, no. 49 (October 9, 2007): 35604–11. http://dx.doi.org/10.1074/jbc.m704047200.

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von Willebrand factor (VWF) is the largest multimeric adhesion ligand circulating in blood. Its adhesion activity is related to multimer size, with the ultra-large forms freshly released from the activated endothelial cells being most active, capable of spontaneously binding to platelets. In comparison, smaller plasma forms circulating in blood bind platelets only under high fluid shear stress or induced by modulators. The structure-function relationships that distinguish the two types of VWF multimers are not known. In this study, we demonstrate that some of the plasma VWF multimers contain surface-exposed free thiols. Physiological and pathological levels of shear stresses (50 and 100 dynes/cm2) promote the formation of disulfide bonds utilizing these free thiols. The shear-induced thiol-disulfide exchange increases VWF binding to platelets. The thiol-disulfide exchange involves some or all of nine cysteine residues (Cys889, Cys898, Cys2448, Cys2451, Cys2490, Cys2491, Cys2453, Cys2528, and Cys2533) in the D3 and C domains as determined by mass spectrometry of the tryptic VWF peptides. These results suggest that the thiol-disulfide state may serve as an important structural determinant of VWF adhesion activity and can be modified by fluid shear stress.
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4

Lahav, Judith, Kerstin Jurk, Oded Hess, Michael J. Barnes, Richard W. Farndale, Jacob Luboshitz, and Beate E. Kehrel. "Sustained integrin ligation involves extracellular free sulfhydryls and enzymatically catalyzed disulfide exchange." Blood 100, no. 7 (October 1, 2002): 2472–78. http://dx.doi.org/10.1182/blood-2001-12-0339.

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Studies have suggested a pivotal role for free sulfhydryls in platelet integrin function, and enzyme-mediated reduction of disulfide bonds on platelets has been implicated. The platelet fibrinogen receptor αIIbβ3 is the best-studied platelet integrin and serves as a model system for studying the structure-function relation in this family of adhesion receptors. The demonstration of free sulfhydryls on the exofacial domain of purified αIIbβ3, specifically in its activated conformation, prompted us to explore the potential for activation-dependent, enzymatically catalyzed thiol expression on intact platelets and the possible role of surface-associated protein disulfide isomerase (PDI) in αIIbβ3 ligation. Using the membrane-impermeant sulfhydryl blocker para-chloromercuriphenyl sulfonate, the inhibitor of disulfide exchange bacitracin, and the monoclonal anti-PDI antibody RL90, we examined fibrinogen binding to αIIbβ3 as well as ligation-induced allosteric changes in the conformation of αIIbβ3. We sought to distinguish the possible involvement of disulfide exchange in agonist-induced platelet stimulation from its role in integrin ligation. Analysis of the role of free thiols in platelet aggregation suggested a thiol-independent initial ligation followed by a thiol-dependent stabilization of binding. Flow cytometric analysis showed that sustained binding of fibrinogen, as well as expression of ligand-induced binding site epitopes and ligand-bound conformation, depended on free thiols and disulfide exchange. Expression of P-selectin was minimally affected, even with complete inhibition of αIIbβ3function. These data indicate that although agonist-induced platelet stimulation is independent of ecto-sulfhydryls, engagement of integrin αIIbβ3 on the intact platelet depends totally on their enzymatically catalyzed surface expression.
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5

Ramasamy, Somasundaram, Tapan K. Kundu, William Antholine, Periakaruppan T. Manoharan, and Joseph M. Rifkind. "Internal spin trapping of thiyl radical during the complexation and reduction of cobalamin with glutathione and dithiothrietol." Journal of Porphyrins and Phthalocyanines 16, no. 01 (January 2012): 25–38. http://dx.doi.org/10.1142/s1088424611004051.

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The activation of cobalamin requires a reduction from cobalamin(III) to cobalamin(II). The reduction by glutathione and dithiothreitol was followed using visible spectroscopy and electron paramagnetic resonance. In addition the oxidation of glutathione was monitored. Glutathione first reacts with oxidized cobalamin(III). The binding of a second glutathione required for the reduction to cobalamin(II) is presumably located in the dimethyl benzimidazole ribonucleotide ligand cavity. The reduction of cobalamin(III) by dithiothreitol, which contains two thiols, is much faster even though no stable cobalamin(III) complex is formed. The reduction, by both thiol reagents, results in the formation of thiyl radicals, some of which are released to form oxidized thiol products and some of which remain associated with the reduced cobalamin. In the reduced state the intrinsic lower affinity for the benzimidazole base, coupled with a trans effect from the initial glutathione bound to the β-axial site and a possible lowering of the pH results in an equilibrium between base-on and base-off complexes. The dissociation of the base facilitates a closer approach of the thiyl radical to the cobalamin(II) α-axial site resulting in a complex with ferromagnetic exchange coupling between the metal ion and the thiyl radical. This is a unique example of "internal spin trapping" of a thiyl radical formed during reduction. The finding that the reduction involves a peripheral site and that thiyl radicals produced during the reduction remain associated with the reduced cobalamin provide important new insights into our understanding of the formation and function of cobalamin enzymes.
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6

Jones, Dean P. "Radical-free biology of oxidative stress." American Journal of Physiology-Cell Physiology 295, no. 4 (October 2008): C849—C868. http://dx.doi.org/10.1152/ajpcell.00283.2008.

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Free radical-induced macromolecular damage has been studied extensively as a mechanism of oxidative stress, but large-scale intervention trials with free radical scavenging antioxidant supplements show little benefit in humans. The present review summarizes data supporting a complementary hypothesis for oxidative stress in disease that can occur without free radicals. This hypothesis, which is termed the “redox hypothesis,” is that oxidative stress occurs as a consequence of disruption of thiol redox circuits, which normally function in cell signaling and physiological regulation. The redox states of thiol systems are sensitive to two-electron oxidants and controlled by the thioredoxins (Trx), glutathione (GSH), and cysteine (Cys). Trx and GSH systems are maintained under stable, but nonequilibrium conditions, due to a continuous oxidation of cell thiols at a rate of about 0.5% of the total thiol pool per minute. Redox-sensitive thiols are critical for signal transduction (e.g., H-Ras, PTP-1B), transcription factor binding to DNA (e.g., Nrf-2, nuclear factor-κB), receptor activation (e.g., αIIbβ3 integrin in platelet activation), and other processes. Nonradical oxidants, including peroxides, aldehydes, quinones, and epoxides, are generated enzymatically from both endogenous and exogenous precursors and do not require free radicals as intermediates to oxidize or modify these thiols. Because of the nonequilibrium conditions in the thiol pathways, aberrant generation of nonradical oxidants at rates comparable to normal oxidation may be sufficient to disrupt function. Considerable opportunity exists to elucidate specific thiol control pathways and develop interventional strategies to restore normal redox control and protect against oxidative stress in aging and age-related disease.
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7

Arican, Sule, Gulcin Hacibeyoglu, Sinan Oguzhan Ulukaya, Gamze Avcioglu, Ruhiye Reisli, Sema Tuncer Uzun, and Ozcan Erel. "Ischemia-modified albumin (IMA) and dynamic thiol-disulfide homeostasis in patients with postherpetic neuralgia." Journal of Laboratory Medicine 43, no. 5 (October 25, 2019): 257–63. http://dx.doi.org/10.1515/labmed-2018-0211.

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Abstract Background Ischemia-modified albumin (IMA) is an isotype of albumin that increases under oxidative stress, and plasma thiols are main defense mechanisms against oxidative stress. The objective of this study was to investigate thiol-disulfide homeostasis and serum IMA levels in postherpetic neuralgia (PHN) patients. Methods A total of 29 PHN patients and 30 healthy controls were included in the study. Serum total and native thiol concentrations and serum disulfide concentration were measured using the method described by Erel and Neselioglu. The albumin cobalt binding test was used to measure serum IMA levels. Results Serum IMA levels were 1.21 ± 0.58 AU and 0.75 ± 0.09 AU in the PHN and control groups, respectively (p < 0.001). Serum total thiol concentrations were found to be 421.62 ± 90.28 μmol/L and 598.36 ± 73.63 μmol/L in the PHN and control groups, respectively (p < 0.001). Serum native thiol concentrations were found to be 365.75 ± 92.07 μmol/L and 531.90 ± 72.9 μmol/L in the PHN and control groups, respectively (p < 0.001). Serum disulfide concentrations were found to be 33.23 ± 5.33 μmol/L and 27.93 ± 7.81 μmol/L in the PHN and control groups, respectively (p = 0.003). The native thiol/total thiol ratio was significantly lower, and the disulfide/total thiol and disulfide/native thiol ratios were significantly higher in the PHN group compared to the controls. Conclusions IMA levels are high and dynamic thiol/disulfide homeostasis is disrupted in PHN patients.
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8

Tong, Ka-Chung, Chun-Nam Lok, Pui-Ki Wan, Di Hu, Yi Man Eva Fung, Xiao-Yong Chang, Song Huang, Haibo Jiang, and Chi-Ming Che. "An anticancer gold(III)-activated porphyrin scaffold that covalently modifies protein cysteine thiols." Proceedings of the National Academy of Sciences 117, no. 3 (January 2, 2020): 1321–29. http://dx.doi.org/10.1073/pnas.1915202117.

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Cysteine thiols of many cancer-associated proteins are attractive targets of anticancer agents. Herein, we unequivocally demonstrate a distinct thiol-targeting property of gold(III) mesoporphyrin IX dimethyl ester (AuMesoIX) and its anticancer activities. While the binding of cysteine thiols with metal complexes usually occurs via M–S bond formation, AuMesoIX is unique in that the meso-carbon atom of the porphyrin ring is activated by the gold(III) ion to undergo nucleophilic aromatic substitution with thiols. AuMesoIX was shown to modify reactive cysteine residues and inhibit the activities of anticancer protein targets including thioredoxin, peroxiredoxin, and deubiquitinases. Treatment of cancer cells with AuMesoIX resulted in the formation of gold-bound sulfur-rich protein aggregates, oxidative stress-mediated cytotoxicity, and accumulation of ubiquitinated proteins. Importantly, AuMesoIX exhibited effective antitumor activity in mice. Our study has uncovered a gold(III)-induced ligand scaffold reactivity for thiol targeting that can be exploited for anticancer applications.
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9

Sokoloff, A. V., T. Whalley, and J. Zimmerberg. "Characterization of N-ethylmaleimide-sensitive thiol groups required for the GTP-dependent fusion of endoplasmic reticulum membranes." Biochemical Journal 312, no. 1 (November 15, 1995): 23–30. http://dx.doi.org/10.1042/bj3120023.

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The GTP-dependent fusion activity of endoplasmic reticulum membranes is thought to be required for the structural maintenance and post-mitotic regeneration of the endoplasmic reticulum. This fusion is sensitive to the thiol-alkylating agent N-ethylmaleimide. In many intracellular fusion events N-ethylmaleimide-sensitivity is associated with a homotrimeric ATPase called N-ethylmaleimide-sensitive fusion protein or NSF. The addition of cytosol containing NSF is known to restore fusion activity to N-ethylmaleimide-treated membranes. We found that the inhibition of fusion of rat liver endoplasmic reticulum membranes (microsomes) by N-ethylmaleimide was not reversed by the addition of untreated cytosol. Fusion was also unaffected by treatment with a buffer known to remove NSF from membranes. Accordingly, no membrane-associated NSF was detected by immunoblot analysis. These data suggest that microsome fusion requires an N-ethylmaleimide-sensitive component distinct from NSF. This component was tightly associated with the membranes, so we used a number of chemical probes to characterize it in situ. Its thiol groups did not appear to be part of a GTP-binding site. They showed relatively low reactivity with sodium periodate, which induces the formation of disulphide bonds between proximate thiol groups. The thiols were not protected against N-ethylmaleimide by Zn2+, a potent inhibitor of fusion which is known to efficiently co-ordinate thiol groups. To characterize the topology of the fusion-related thiol groups we used bulky thiol-specific reagents prepared by conjugating BSA or 10 kDa aminodextran to the bifunctional reagent N-succinimidyl 3-(2-pyridyldithio)propionate. The inhibition of fusion by these reagents indicated that these thiols are highly exposed on the membranes. This exposure might be important for the function of these groups during GTP-triggered fusion.
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10

White, Kylie, Gina Nicoletti, and Hugh Cornell. "Antibacterial Profile of a Microbicidal Agent Targeting Tyrosine Phosphatases and Redox Thiols, Novel Drug Targets." Antibiotics 10, no. 11 (October 27, 2021): 1310. http://dx.doi.org/10.3390/antibiotics10111310.

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The activity profile of a protein tyrosine phosphatase (PTP) inhibitor and redox thiol oxidant, nitropropenyl benzodioxole (NPBD), was investigated across a broad range of bacterial species. In vitro assays assessed inhibitory and lethal activity patterns, the induction of drug variants on long term exposure, the inhibitory interactions of NPBD with antibiotics, and the effect of plasma proteins and redox thiols on activity. A literature review indicates the complexity of PTP and redox signaling and suggests likely metabolic targets. NPBD was broadly bactericidal to pathogens of the skin, respiratory, urogenital and intestinal tracts. It was effective against antibiotic resistant strains and slowly replicating and dormant cells. NPBD did not induce resistant or drug-tolerant phenotypes and showed low cross reactivity with antibiotics in synergy assays. Binding to plasma proteins indicated lowered in-vitro bioavailability and reduction of bactericidal activity in the presence of thiols confirmed the contribution of thiol oxidation and oxidative stress to lethality. This report presents a broad evaluation of the antibacterial effect of PTP inhibition and redox thiol oxidation, illustrates the functional diversity of bacterial PTPs and redox thiols, and supports their consideration as novel targets for antimicrobial drug development. NPBD is a dual mechanism agent with an activity profile which supports consideration of tyrosine phosphatases and bacterial antioxidant systems as promising targets for drug development.
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11

Solecka, Barbara, Birte Fuchs, Christoph Weise, and Christoph Kannicht. "Free Thiol Groups In Von Willebrand Factor (VWF) Are Required For Its Proper Function Under Physiological Flow Conditions." Blood 122, no. 21 (November 15, 2013): 2338. http://dx.doi.org/10.1182/blood.v122.21.2338.2338.

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Abstract Background The multimeric plasma glycoprotein von Willebrand factor (VWF) is exceptionally rich in cysteine, and its structure is largely determined by inter- and intramolecular disulfide bonding. Additionally, VWF was shown to contain unpaired cysteine residues potentially affecting protein function. The significance of free thiols on the surface of plasmatic VWF has been confirmed previously with respect to platelet binding under pathologically high shear stress. Furthermore their potential involvement in functional VWF self-association occurring at elevated shear stress has been suggested. Aims Objective of the present study was to investigate whether free thiol groups of plasma VWF contribute to the physiological VWF function under high physiological arterial shear stress conditions. Furthermore, we aimed to elucidate possible underlying mechanisms involved in this regulation. Methods Free and accessible thiol groups of plasma-derived VWF were blocked with N-ethylmaleimide (NEM). Derivatization was followed by detailed structural and functional examination including multimer analysis (MMA) and Fourier transform infrared spectroscopy (FTIR). Functional differences between the NEM-derivatized sample and the control sample were detected using an in vitro flow chamber system with respect to VWF-mediated platelet adhesion to collagen. Interactions with collagen type III and platelet glycoprotein (GP)Ib receptor were investigated using surface plasmon resonance (SPR). Identification of accessible cysteine residues was accomplished using biotin-linked maleimide (MPB) followed by analysis of multimer and domain incorporation as well as mass spectrometry. Results Blocking free thiol groups provoked substantial loss of VWF activity with respect to platelet recruitment to collagen type III under flow. The lowered platelet adhesion to collagen type III was shown to be a combined effect of inhibition of (i) the initial VWF binding to collagen type III as well as (ii) VWF-platelet GPIb interaction. Free thiol groups were accessible for derivatization solely on the surface of coiled multimers. Domain incorporation studies revealed a high level of derivatization in VWF N- and C-terminus. This was in accordance with the mass spectrometric analysis, where 19 MPB-derivatized peptides, predominantly located at the N- and C-terminus, could be identified. Conclusion Blocking free thiol groups in VWF significantly impaired mediation of platelet adhesion under physiological shear stress conditions. This result suggests an essential functional role of free thiol groups in VWF regarding binding to subendothelial matrix as well as platelet recruitment. Disclosures: Solecka: Octapharma AG: Employment. Fuchs:Octapharma AG: Employment. Kannicht:Octapharma AG: Employment.
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12

Nikolaev, Anton, Iryna Makarchuk, Alexander Thesseling, Jo Hoeser, Thorsten Friedrich, Frédéric Melin, and Petra Hellwig. "Stabilization of the Highly Hydrophobic Membrane Protein, Cytochrome bd Oxidase, on Metallic Surfaces for Direct Electrochemical Studies." Molecules 25, no. 14 (July 16, 2020): 3240. http://dx.doi.org/10.3390/molecules25143240.

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The cytochrome bd oxidase catalyzes the reduction of oxygen to water in bacteria and it is thus an interesting target for electrocatalytic studies and biosensor applications. The bd oxidase is completely embedded in the phospholipid membrane. In this study, the variation of the surface charge of thiol-modified gold nanoparticles, the length of the thiols and the other crucial parameters including optimal phospholipid content and type, have been performed, giving insight into the role of these factors for the optimal interaction and direct electron transfer of an integral membrane protein. Importantly, all three tested factors, the lipid type, the electrode surface charge and the thiol length mutually influenced the stability of films of the cytochrome bd oxidase. The best electrocatalytic responses were obtained on the neutral gold surface when the negatively charged phosphatidylglycerol (PG) was used and on the charged gold surface when the zwitterionic phosphatidylethanolamine (PE) was used. The advantages of the covalent binding of the membrane protein to the electrode surface over the non-covalent binding are also discussed.
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Park, Jun Hyung, Buyng Su Park, Gu Huh, Seung Hyun Lee, Hyun Sook Lee, Il Hoon Cho, Se Hwan Paek, and Hai Won Lee. "Specific Immobilization of Streptavidin on Mixed Self-Assembled Monolayers as Mixing Ratio." Solid State Phenomena 121-123 (March 2007): 495–98. http://dx.doi.org/10.4028/www.scientific.net/ssp.121-123.495.

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We report on the distribution of mixed self-assembled monolayers (SAMs) composed of biotinylated and diluent alkylthiolates for streptavidin immobilization. Two thiol derivatives, 11-mercapto-1-undecanol (MUOH) and 11-mercaptoundecanoic-(8-biotinylamido-3,6-dioxaoctyl) amide (MBDA), were employed for mixed SAM. These thiols formed self-assembled monolayer without local domain, and streptavidins were immobilized onto biotinylated gold surface without nonspecific binding. In order to find the optimized condition of immobilization of streptavidin, we controlled the mixing ratio of two kind thiols by colorimetric detection assay, and the immobilization was characterized by atomic force microscopy (AFM), scanning tunneling microscopy (STM), and ellipsometer.
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14

Hou, Yong, Qingyou Xia, and Y. Adam Yuan. "Crystal structure of Bombyx mori nucleopolyhedrovirus ORF75 reveals a pseudo-dimer of thiol oxidase domains with a putative substrate-binding pocket." Journal of General Virology 93, no. 10 (October 1, 2012): 2142–51. http://dx.doi.org/10.1099/vir.0.042747-0.

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Bombyx mori nucleopolyhedrovirus (BmNPV) triggers the global shutdown of host silkworm gene expression and protein synthesis approximately 12–18 h post-infection. Genome sequence analysis suggests that BmNPV ORF75 could be a flavin adenine dinucleotide (FAD)-linked thiol oxidase essential for virion assembly and virus propagation. Here, we report the crystal structure of BmNPV ORF75 at 2.1 Å (0.21 nm). The structure of BmNPV ORF75 resembles that of the thiol oxidase domain of human quiescin thiol oxidase (QSOX), displaying a pseudo-dimer of canonical and non-canonical thiol oxidase domains. However, BmNPV ORF75 is further dimerized by its C-terminal canonical thiol oxidase domain. Within the unique quaternary structural arrangement, the FAD-binding pocket and the characteristic CXXC motif from each monomer is 35 Å (3.5 nm) away from that of its corresponding molecule, which suggests that BmNPV ORF75 might adopt a deviant mechanism from that of QSOX to catalyse disulfide bond formation. Our thiol oxidase activity assay on the point mutations of the conserved residues participating in FAD recognition reveals an aromatic cage next to the FAD isoalloxazine moiety for substrate binding. These data suggest that the thiol oxidase activity of BmNPV ORF75 could be critical to catalyse the formation of the disulfide bonds of certain BmNPV proteins essential for BmNPV virion assembly.
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15

Li, Zhipeng, Wei Xiong, Xiaojun He, Xiaoliang Qi, Feng Ding, and Jianliang Shen. "A novel strategy for rhodamine B-based fluorescent probes with a selective glutathione response for bioimaging in living cells." Analyst 145, no. 12 (2020): 4239–44. http://dx.doi.org/10.1039/d0an00582g.

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The aim of this study was to overcome the reported shortcomings of the glutathione (GSH) detection of rhodamine-based fluorescent probes, such as poor selectivity to thiol groups and reversible unstable covalent binding with the thiol groups.
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Salvarezza, Roberto Carlos, and Pilar Carro. "Exploring the core level shift origin of sulfur and thiolates on Pd(111) surfaces." Physical Chemistry Chemical Physics 17, no. 37 (2015): 24349–55. http://dx.doi.org/10.1039/c5cp04180e.

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DFT calculations show that the core level shift (CLS) of the S 2p binding energy of thiol and sulfur atoms on different thiol–Pd(111) surfaces strongly depends on the adsorbed or subsurface state of sulfur atoms.
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Xu, Yan, Xiao-Sheng Yan, Si-Bo Zhang, Shao-Wei Li, Ning-Shao Xia, Tao Jiang, Zhao Li, and Yun-Bao Jiang. "Nanospheres from coordination polymers of Ag+ with a highly hydrophilic thiol ligand formed in situ from dynamic covalent binding and a hydrophobic thiol." New Journal of Chemistry 45, no. 42 (2021): 19957–62. http://dx.doi.org/10.1039/d1nj03609b.

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A supramolecular nanosphere with a diameter of 8.7 nm is obtained in an aqueous alkaline solution via glucose binding to a boronic acid-based thiol (4-MPBA) as a hydrophilic ligand, together with a hydrophobic thiol ligand n-C8H17SH.
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18

LJUNGQUIST, Charlotta, Birger JANSSON, Tomas MOKS, and Mathias UHLEN. "Thiol-directed immobilization of recombinant IgG-binding receptors." European Journal of Biochemistry 186, no. 3 (December 1989): 557–61. http://dx.doi.org/10.1111/j.1432-1033.1989.tb15244.x.

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19

Palmer, M. "The family of thiol-activated, cholesterol-binding cytolysins." Toxicon 39, no. 11 (November 2001): 1681–89. http://dx.doi.org/10.1016/s0041-0101(01)00155-6.

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20

Billinge, Simon J. L., Emily J. McKimmy, Mouath Shatnawi, HyunJeong Kim, Valeri Petkov, Didier Wermeille, and Thomas J. Pinnavaia. "Mercury Binding Sites in Thiol-Functionalized Mesostructured Silica." Journal of the American Chemical Society 127, no. 23 (June 2005): 8492–98. http://dx.doi.org/10.1021/ja0506859.

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21

Krzykawska, A., J. Ossowski, T. Żaba, and P. Cyganik. "Binding groups for highly ordered SAM formation: carboxylic versus thiol." Chemical Communications 53, no. 42 (2017): 5748–51. http://dx.doi.org/10.1039/c7cc01939d.

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22

Chillé, Donatella, Viviana Mollica-Nardo, Ottavia Giuffrè, Rosina Celeste Ponterio, Franz Saija, Jiří Sponer, Sebastiano Trusso, Giuseppe Cassone, and Claudia Foti. "Binding of Arsenic by Common Functional Groups: An Experimental and Quantum-Mechanical Study." Applied Sciences 12, no. 6 (March 21, 2022): 3210. http://dx.doi.org/10.3390/app12063210.

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Arsenic is a well-known contaminant present in different environmental compartments and in human organs and tissues. Inorganic As(III) represents one of the most dangerous arsenic forms. Its toxicity is attributed to its great affinity with the thiol groups of proteins. Considering the simultaneous presence in all environmental compartments of other common functional groups, we here present a study aimed at evaluating their contribution to the As(III) complexation. As(III) interactions with four (from di- to hexa-) carboxylic acids, five (from mono- to penta-) amines, and four amino acids were evaluated via experimental methods and, in simplified systems, also by quantum-mechanical calculations. Data were analyzed also with respect to those previously reported for mixed thiol-carboxylic ligands to evaluate the contribution of each functional group (-SH, -COOH, and -NH2) toward the As(III) complexation. Formation constants of As(III) complex species were experimentally determined, and data were analyzed for each class of ligand. An empirical relationship was reported, taking into account the contribution of each functional group to the complexation process and allowing for a rough estimate of the stability of species in systems where As(III) and thiol, carboxylic, or amino groups are involved. Quantum-mechanical calculations allowed for the evaluation and the characterization of the main chelation reactions of As(III). The potential competitive effects of the investigated groups were evaluated using cysteine, a prototypical species possessing all the functional groups under investigation. Results confirm the higher binding capabilities of the thiol group under different circumstances, but also indicate the concrete possibility of the simultaneous binding of As(III) by the thiol and the carboxylic groups.
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Zhou, Zhou, Hiuwan Choi, Zhenyin Tao, Khatira Aboulfatova, Leticia Nolasco, Joel L. Moake, and Jing-fei Dong. "ADAMTS-13 Has a Disulfide Bond Reduction Activity on Von Willebrand Factor." Blood 112, no. 11 (November 16, 2008): 3934. http://dx.doi.org/10.1182/blood.v112.11.3934.3934.

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Abstract Von Willebrand factor (VWF) multimers tether platelets to subendothelium exposed at the site of vessel injury to initiate the bleeding arrest. Upon synthesized, VWF multimers are either constitutively secreted or packed into the storage granules, where they are enriched in ultra-large (UL) multimers that are active in forming spontaneous high strength bonds with the GP Ib-IX-V complex on platelets. This hyper-reactivity of ULVWF multimers is in contrast to VWF multimers circulating in plasma (pVWF) that need to be activated by modulators or high fluid shear stress to aggregate platelets. The biochemical and structural bases for the functional difference between ULVWF and pVWF multimers are not known. We have recently shown that a portion of pVWF, but not ULVWF multimers contain surface exposed free thiols in the D3 and C domains. High fluid shear stress promotes the formation of new disulfide bonds utilizing the thiols to enhance VWF binding to platelets, suggesting that the shear-induced thiol-disulfide exchange may serve as a mechanism for the shear-induced activation of pVWF multimers. ULVWF freshly secreted from endothelial cells forms string-like structures that can be elongated by pVWF multimers through a covalent means. The different thiol distribution between ULVWF and its plasma counterpart may be caused by the former being cleaved by the zinc metalloprotease ADAMTS-13 at a single peptide bond of Y1065-M1606 in the A2 domain. Here, we provide several lines of evidence to demonstrate that ADAMTS-13 also contains a reductase-like activity that plays a role in cleaving ULVWF strings under flow conditions and maintaining circulating VWF multimers in an inactive (thiol) state. First, more than 90% of pVWF non-specifically adhered to the surface of a cone-plate viscometer when pVWF was exposed to a pathological high shear stress of 100 dyn/cm2 for 3 min at 37°C. The adhesion was prevented by recombinant (r) ADAMTS-13 or a truncation mutant that lacked the catalytic domain. Second, rADAMTS-13 prevented the shear-induced thiol-disulfide exchange so that free thiols remained in pVWF after shear exposure. This activity was not blocked by 5 mM of EDTA and was detectable with the N-terminal truncated mutant, suggesting that it is independent of the VWF-cleaving activity. We further found that rADAMTS-13 was able to reduce disulfide bonds, converting the disulfide forms of sheared pVWF to the thiol forms, suggesting that ADAMTS-13 prevents the thiol-disulfide exchange by disulfide bond reduction, not a steric hindered effect. Third, ADAMTS-13 contains the surface exposed thiol(s) that is necessary for the metalloprotease to attack and break a disulfide bond. Unlike VWF multimers, these thiols remained after the metalloprotease was exposed to a pathological high shear stress of 100 dyn/cm2. Fourth, using a series of N- and C-terminal truncation mutants, we located the thiol(s) potentially involved in VWF reduction to the 2nd to 8th TSP-1 motifs and CUB-1 domain of ADAMTS-13. Finally, ethylmaleimide (NEM), which blocks free thiols, did not inhibit rADAMTS-13 to cleave pVWF multimers under static conditions and in the presence of urea and barium. NEM-treated rADAMTS-13 retained only 27.5±4.9% activity in cleaving ULVWF strings under flow conditions as compared to untreated enzyme. These data characterizes a novel mechanism that plays a regulatory role in cleaving ULVWF strings and maintaining the circulating pVWF multimers in inactive forms.
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Morgan, M. S., R. M. Darrow, M. A. Nafz, and P. T. Varandani. "Participation of cellular thiol/disulphide groups in the uptake, degradation and bioactivity of insulin in primary cultures of rat hepatocytes." Biochemical Journal 225, no. 2 (January 15, 1985): 349–56. http://dx.doi.org/10.1042/bj2250349.

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The effects on the uptake (cell-associated 125I) and degradation (125I-labelled products released into the medium) of 125I-insulin and bioactivity (protein, glycogen and lipid synthesis) of insulin caused by altering the cellular thiol/disulphide status in primary cultures of rat hepatocytes were studied. Incubation of hepatocyte cultures with various exogenous thiol compounds (reduced glutathione, 2-mercaptoethanol, cysteamine, dithiothreitol) resulted in increased insulin binding, but markedly decreased degradation and bioactivity. These effects could be reversed by washing or by the addition of oxidized glutathione, which alone had no effect. When cultures were exposed to certain thiol-modifying reagents (N-ethylmaleimide, p-chloromercuribenzoate, p-chloromercuribenzenesulphonate, iodoacetamide, iodoacetate), some decreases in bioactivity were evident, but the pronounced decrease in insulin degradation observed with the thiol-containing compounds was not observed with this class of compounds. None of the thiol-containing or -modifying agents tested had any significant effect on cellular ATP concentrations, indicating that the effects observed were due to perturbation of the thiol/disulphide status. Depletion of intracellular glutathione by DL-buthionine SR-sulphoximine (a specific inhibitor of glutathionine biosynthesis) decreased the syntheses of glycogen and lipid by about one-half, while having essentially no effect on protein synthesis, ATP concentrations or on the binding and degradation of insulin. The data presented here indicate that although intracellular thiol (glutathione) concentrations may be important for the maintenance of full expression of certain biological activities (glycogen and lipid synthesis), the thiol/disulphide groups on the cell surface and those immediately inside the cell membrane may be more critical in the mediation of insulin action, including the degradation and bioactivity of insulin in primary cultures of rat hepatocytes.
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25

Wang, Yifan, Ian Davis, Yan Chan, Sunil G. Naik, Wendell P. Griffith, and Aimin Liu. "Characterization of the nonheme iron center of cysteamine dioxygenase and its interaction with substrates." Journal of Biological Chemistry 295, no. 33 (June 28, 2020): 11789–802. http://dx.doi.org/10.1074/jbc.ra120.013915.

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Cysteamine dioxygenase (ADO) has been reported to exhibit two distinct biological functions with a nonheme iron center. It catalyzes oxidation of both cysteamine in sulfur metabolism and N-terminal cysteine-containing proteins or peptides, such as regulator of G protein signaling 5 (RGS5). It thereby preserves oxygen homeostasis in a variety of physiological processes. However, little is known about its catalytic center and how it interacts with these two types of primary substrates in addition to O2. Here, using electron paramagnetic resonance (EPR), Mössbauer, and UV-visible spectroscopies, we explored the binding mode of cysteamine and RGS5 to human and mouse ADO proteins in their physiologically relevant ferrous form. This characterization revealed that in the presence of nitric oxide as a spin probe and oxygen surrogate, both the small molecule and the peptide substrates coordinate the iron center with their free thiols in a monodentate binding mode, in sharp contrast to binding behaviors observed in other thiol dioxygenases. We observed a substrate-bound B-type dinitrosyl iron center complex in ADO, suggesting the possibility of dioxygen binding to the iron ion in a side-on mode. Moreover, we observed substrate-mediated reduction of the iron center from ferric to the ferrous oxidation state. Subsequent MS analysis indicated corresponding disulfide formation of the substrates, suggesting that the presence of the substrate could reactivate ADO to defend against oxidative stress. The findings of this work contribute to the understanding of the substrate interaction in ADO and fill a gap in our knowledge of the substrate specificity of thiol dioxygenases.
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26

Davies, Joshua, Carol Thomas, Mohammad Rizwan, and Christopher Gwenin. "Development of Electrochemical DNA Biosensor for Equine Hindgut Acidosis Detection." Sensors 21, no. 7 (March 26, 2021): 2319. http://dx.doi.org/10.3390/s21072319.

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The pH drop in the hindgut of the horse is caused by lactic acid-producing bacteria which are abundant when a horse’s feeding regime is excessively carbohydrate rich. This drop in pH below six causes hindgut acidosis and may lead to laminitis. Lactic acid-producing bacteria Streptococcus equinus and Mitsuokella jalaludinii have been found to produce high amounts of L-lactate and D-lactate, respectively. Early detection of increased levels of these bacteria could allow the horse owner to tailor the horse’s diet to avoid hindgut acidosis and subsequent laminitis. Therefore, 16s ribosomal ribonucleic acid (rRNA) sequences were identified and modified to obtain target single stranded deoxyribonucleic acid (DNA) from these bacteria. Complementary single stranded DNAs were designed from the modified target sequences to form capture probes. Binding between capture probe and target single stranded deoxyribonucleic acid (ssDNA) in solution has been studied by gel electrophoresis. Among pairs of different capture probes and target single stranded DNA, hybridization of Streptococcus equinus capture probe 1 (SECP1) and Streptococcus equinus target 1 (SET1) was portrayed as gel electrophoresis. Adsorptive stripping voltammetry was utilized to study the binding of thiol modified SECP1 over gold on glass substrates and these studies showed a consistent binding signal of thiol modified SECP1 and their hybridization with SET1 over the gold working electrode. Cyclic voltammetry and electrochemical impedance spectroscopy were employed to examine the binding of thiol modified SECP1 on the gold working electrode and hybridization of thiol modified SECP1 with the target single stranded DNA. Both demonstrated the gold working electrode surface was modified with a capture probe layer and hybridization of the thiol bound ssDNA probe with target DNA was indicated. Therefore, the proposed electrochemical biosensor has the potential to be used for the detection of the non-synthetic bacterial DNA target responsible for equine hindgut acidosis.
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27

Khan, Samir A., Ana M. Rossi, Andrew M. Riley, Barry V. L. Potter, and Colin W. Taylor. "Subtype-selective regulation of IP3 receptors by thimerosal via cysteine residues within the IP3-binding core and suppressor domain." Biochemical Journal 451, no. 2 (March 28, 2013): 177–84. http://dx.doi.org/10.1042/bj20121600.

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IP3R (IP3 [inositol 1,4,5-trisphosphate] receptors) and ryanodine receptors are the most widely expressed intracellular Ca2+ channels and both are regulated by thiol reagents. In DT40 cells stably expressing single subtypes of mammalian IP3R, low concentrations of thimerosal (also known as thiomersal), which oxidizes thiols to form a thiomercurylethyl complex, increased the sensitivity of IP3-evoked Ca2+ release via IP3R1 and IP3R2, but inhibited IP3R3. Activation of IP3R is initiated by IP3 binding to the IBC (IP3-binding core; residues 224–604) and proceeds via re-arrangement of an interface between the IBC and SD (suppressor domain; residues 1–223). Thimerosal (100 μM) stimulated IP3 binding to the isolated NT (N-terminal; residues 1–604) of IP3R1 and IP3R2, but not to that of IP3R3. Binding of a competitive antagonist (heparin) or partial agonist (dimeric-IP3) to NT1 was unaffected by thiomersal, suggesting that the effect of thimerosal is specifically related to IP3R activation. IP3 binding to NT1 in which all cysteine residues were replaced by alanine was insensitive to thimerosal, so too were NT1 in which cysteine residues were replaced in either the SD or IBC. This demonstrates that thimerosal interacts directly with cysteine in both the SD and IBC. Chimaeric proteins in which the SD of the IP3R was replaced by the structurally related A domain of a ryanodine receptor were functional, but thimerosal inhibited both IP3 binding to the chimaeric NT and IP3-evoked Ca2+ release from the chimaeric IP3R. This is the first systematic analysis of the effects of a thiol reagent on each IP3R subtype. We conclude that thimerosal selectively sensitizes IP3R1 and IP3R2 to IP3 by modifying cysteine residues within both the SD and IBC and thereby stabilizing an active conformation of the receptor.
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28

Edmonds, S., A. Gibb, and E. Sim. "Effect of thiol compounds on human complement component C4." Biochemical Journal 289, no. 3 (February 1, 1993): 801–5. http://dx.doi.org/10.1042/bj2890801.

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Thiol compounds have been investigated as inhibitors of the covalent binding reaction of human complement protein C4 using Sepharose-C1s as a combined activating and binding surface. o- and p-substituted aminothiophenols are equally effective inhibitors, whereas the m-substituted compound is a less potent inhibitor. The anti-hypertensive drug captopril is also shown to inhibit the covalent binding reaction. A comparison of the effects of these compounds on the covalent binding reaction of isolated C4A and C4B has been made. Results suggest that a Pro-to-Leu substitution in C4B is likely to account for the differences in inhibitory potency of C4B compared with C4A observed with the aromatic inhibitors.
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29

Gargantilla, Marta, José López-Fernández, Maria-Jose Camarasa, Leentje Persoons, Dirk Daelemans, Eva-Maria Priego, and María-Jesús Pérez-Pérez. "Inhibition of XPO-1 Mediated Nuclear Export through the Michael-Acceptor Character of Chalcones." Pharmaceuticals 14, no. 11 (November 6, 2021): 1131. http://dx.doi.org/10.3390/ph14111131.

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The nuclear export receptor exportin-1 (XPO1, CRM1) mediates the nuclear export of proteins that contain a leucine-rich nuclear export signal (NES) towards the cytoplasm. XPO1 is considered a relevant target in different human diseases, particularly in hematological malignancies, tumor resistance, inflammation, neurodegeneration and viral infections. Thus, its pharmacological inhibition is of significant therapeutic interest. The best inhibitors described so far (leptomycin B and SINE compounds) interact with XPO1 through a covalent interaction with Cys528 located in the NES-binding cleft of XPO1. Based on the well-established feature of chalcone derivatives to react with thiol groups via hetero-Michael addition reactions, we have synthesized two series of chalcones. Their capacity to react with thiol groups was tested by incubation with GSH to afford the hetero-Michael adducts that evolved backwards to the initial chalcone through a retro-Michael reaction, supporting that the covalent interaction with thiols could be reversible. The chalcone derivatives were evaluated in antiproliferative assays against a panel of cancer cell lines and as XPO1 inhibitors, and a good correlation was observed with the results obtained in both assays. Moreover, no inhibition of the cargo export was observed when the two prototype chalcones 9 and 10 were tested against a XPO1-mutated Jurkat cell line (XPO1C528S), highlighting the importance of the Cys at the NES-binding cleft for inhibition. Finally, their interaction at the molecular level at the NES-binding cleft was studied by applying the computational tool CovDock.
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30

Grill, V., and K. Fåk. "Influence of thiol groups, calcium, and glucose metabolism on cholinergic-induced insulin release and on methylscopolamine binding to muscarinic receptors in pancreatic islets of the rat." Acta Endocrinologica 109, no. 3 (July 1985): 355–60. http://dx.doi.org/10.1530/acta.0.1090355.

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Abstract. Short-term regulation of [3H]methylscopolamine binding to muscarinic receptors and acetylcholineinduced stimulation of insulin release was investigated in pancreatic islets of the rat. Binding of methylscopolamine was reversible; 47% of label was displaced 10 min and 70% 30 min after addition of unlabelled substance. 0.1 mm chloromercuribensoic acid, when present during binding incubations, inhibited binding by 54%, whereas acetylcholine-induced insulin release was unaffected by the presence of the thiol reactant. Pre-incubation for 60 min in a calcium-deprived medium or in the presence of 50 μm trifluoroperazine likewise inhibited binding. Pre-incubation with 1.0 mm 3-isobutyl-l-methylxanthine or 16.7 m glucose failed to influence subsequent binding although acetylcholine-induced insulin release was 4-fold enhanced by priming with glucose. We conclude that 1) binding to muscarinic receptors is influenced by thiol interaction, 2) short-term alterations in calcium fluxes influence binding, whereas short-term changes in cyclic AMP (cAMP) or glucose metabolism do not, 3) a priming effect of glucose on insulin secretion is not mediated by changes in receptor binding.
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31

Müller, Andreas, and Burkhard König. "Vesicular aptasensor for the detection of thrombin." Chem. Commun. 50, no. 84 (2014): 12665–68. http://dx.doi.org/10.1039/c4cc05221h.

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32

Gonzalez-Fernandez, Federico, Dongjin Sung, Karen M. Haswell, Andrew Tsin, and Debashis Ghosh. "Thiol-dependent antioxidant activity of interphotoreceptor retinoid-binding protein." Experimental Eye Research 120 (March 2014): 167–74. http://dx.doi.org/10.1016/j.exer.2014.01.002.

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33

Basch, Harold, and Mark A. Ratner. "Molecular binding at gold transport interfaces. IV. Thiol chemisorption." Journal of Chemical Physics 120, no. 12 (March 22, 2004): 5771–80. http://dx.doi.org/10.1063/1.1650294.

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34

Rogers, Arlin B., Kathleen S. Cormier, and James G. Fox. "Thiol-reactive compounds prevent nonspecific antibody binding in immunohistochemistry." Laboratory Investigation 86, no. 5 (March 13, 2006): 526–33. http://dx.doi.org/10.1038/labinvest.3700407.

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35

Wu, X., N. H. Bishopric, D. J. Discher, B. J. Murphy, and K. A. Webster. "Physical and functional sensitivity of zinc finger transcription factors to redox change." Molecular and Cellular Biology 16, no. 3 (March 1996): 1035–46. http://dx.doi.org/10.1128/mcb.16.3.1035.

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Redox regulation of DNA-binding proteins through the reversible oxidation of key cysteine sulfhydryl groups has been demonstrated to occur in vitro for a range of transcription factors. The direct redox regulation of DNA binding has not been described in vivo, possibly because most protein thiol groups are strongly buffered against oxidation by the highly reduced intracellular environment mediated by glutathione, thioredoxin, and associated pathways. For this reason, only accessible protein thiol groups with high thiol-disulfide oxidation potentials are likely to be responsive to intracellular redox changes. In this article, we demonstrate that zinc finger DNA-binding proteins, in particular members of the Sp-1 family, appear to contain such redox-sensitive -SH groups. These proteins displayed a higher sensitivity to redox regulation than other redox-responsive factors both in vitro and in vivo. This effect was reflected in the hyperoxidative repression of transcription from promoters with essential Sp-1 binding sites, including the simian virus 40 early region, glycolytic enzyme, and dihydrofolate reductase genes. Promoter analyses implicated the Sp-1 sites in this repression. Non-Sp-1-dependent redox-regulated genes including metallothionein and heme oxygenase were induced by the same hyperoxic stress. The studies demonstrate that cellular redox changes can directly regulate gene expression in vivo by determining the level of occupancy of strategically positioned GC-binding sites.
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36

Yamauchi, Akira, and Eda T. Bloom. "Control of Cell Cycle Progression in Human Natural Killer Cells Through Redox Regulation of Expression and Phosphorylation of Retinoblastoma Gene Product Protein." Blood 89, no. 11 (June 1, 1997): 4092–99. http://dx.doi.org/10.1182/blood.v89.11.4092.

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Abstract Using thiol deprivation, we have previously shown that the response of natural killer (NK) cells to interleukin-2 (IL-2) is subject to redox regulation downstream of IL-2 binding and internalization. We have now used the IL-2–dependent cell line, NK3.3 to study redox regulation of NK cells further, and found that NK3.3 cells neither incorporated [3H]-thymidine nor completed the G1-S phase transition in medium lacking the thiol-related compounds, L-cystine, and glutathione, despite the presence of sufficient IL-2. Thiol deprivation did not alter the induction of DNA interferon-γ activated sequence (GAS)-binding activity in response to IL-2. However, the retinoblastoma gene product (RB), a cyclin-dependent kinase (CDK) substrate, was phosphorylated within 24 hours after IL-2 stimulation in standard medium, but its expression and phosphorylation were reduced in thiol-depleted medium in both NK3.3 cells and freshly isolated NK cells. These reductions were not associated with an increased level of p27Kip1, an inhibitor of CDKs CDK6/2 in association with G1 cyclins. Reducing agents, N-acetylcysteine, reduced glutathione or 2-ME restored both RB phosphorylation and DNA synthesis in thiol-deprived NK3.3 cells. The in vitro kinase activities of CDK6 and CDK2 were prematurely increased by thiol deprivation. This enhancement was associated with CDK hyperphosphorylation and prolonged phosphorylation, and could be observed before and beyond IL-2 stimulation. The data suggest the possibility that the premature and prolonged enhancement of CDK activity in thiol-deprived NK cells is associated with, and therefore may contribute to, the reduced expression and phosphorylation of RB, and the associated cell cycle arrest.
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37

Shiri, Fereshteh, Somaye Shahraki, Sadegh Baneshi, Massoud Nejati-Yazdinejad, and Mostafa Heidari Majd. "Synthesis, characterization, in vitro cytotoxicity, in silico ADMET analysis and interaction studies of 5-dithiocarbamato-1,3,4-thiadiazole-2-thiol and its zinc(ii) complex with human serum albumin: combined spectroscopy and molecular docking investigations." RSC Advances 6, no. 108 (2016): 106516–26. http://dx.doi.org/10.1039/c6ra17322e.

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38

Astorga, Bethzaida, Theresa M. Wunz, Mark Morales, Stephen H. Wright, and Ryan M. Pelis. "Differences in the substrate binding regions of renal organic anion transporters 1 (OAT1) and 3 (OAT3)." American Journal of Physiology-Renal Physiology 301, no. 2 (August 2011): F378—F386. http://dx.doi.org/10.1152/ajprenal.00735.2010.

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This study examined the selectivity of organic anion transporters OAT1 and OAT3 for structural congeners of the heavy metal chelator 2,3-dimercapto-1-propanesulfonic acid (DMPS). Thiol-reactive reagents were also used to test structural predictions based on a homology model of OAT1 structure. DMPS was near equipotent in its ability to inhibit OAT1 (IC50 = 83 μM) and OAT3 (IC50 = 40 μM) expressed in Chinese hamster ovary cells. However, removal of a thiol group (3-mercapto-1-propanesulfonic acid) resulted in a 2.5-fold increase in IC50 toward OAT1 vs. a ∼55-fold increase in IC50 toward OAT3. The data suggested that compound volume/size is important for binding to OAT1/OAT3. The sensitivity to HgCl2 of OAT1 and OAT3 was also dramatically different, with IC50 values of 104 and 659 μM, respectively. Consistent with cysteines of OAT1 being more accessible from the external medium than those of OAT3, thiol-reactive reagents reacted preferentially with OAT1 in cell surface biotinylation assays. OAT1 was less sensitive to HgCl2 inhibition and less reactive toward membrane-impermeant thiol reactive reagents following mutation of cysteine 440 (C440) to an alanine. These data indicate that C440 in transmembrane helix 10 of OAT1 is accessible from the extracellular space. Indeed, C440 was exposed to the aqueous phase of the presumptive substrate translocation pathway in a homology model of OAT1 structure. The limited thiol reactivity in OAT3 suggests that the homologous cysteine residue (C428) is less accessible. Consistent with their homolog-specific selectivities, these data highlight structural differences in the substrate binding regions of OAT1 and OAT3.
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39

Hinchliffe, Philip, Mariano M. González, Maria F. Mojica, Javier M. González, Valerie Castillo, Cecilia Saiz, Magda Kosmopoulou, et al. "Cross-class metallo-β-lactamase inhibition by bisthiazolidines reveals multiple binding modes." Proceedings of the National Academy of Sciences 113, no. 26 (June 14, 2016): E3745—E3754. http://dx.doi.org/10.1073/pnas.1601368113.

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Metallo-β-lactamases (MBLs) hydrolyze almost all β-lactam antibiotics and are unaffected by clinically available β-lactamase inhibitors (βLIs). Active-site architecture divides MBLs into three classes (B1, B2, and B3), complicating development of βLIs effective against all enzymes. Bisthiazolidines (BTZs) are carboxylate-containing, bicyclic compounds, considered as penicillin analogs with an additional free thiol. Here, we show both l- and d-BTZ enantiomers are micromolar competitive βLIs of all MBL classes in vitro, with Kis of 6–15 µM or 36–84 µM for subclass B1 MBLs (IMP-1 and BcII, respectively), and 10–12 µM for the B3 enzyme L1. Against the B2 MBL Sfh-I, the l-BTZ enantiomers exhibit 100-fold lower Kis (0.26–0.36 µM) than d-BTZs (26–29 µM). Importantly, cell-based time-kill assays show BTZs restore β-lactam susceptibility of Escherichia coli-producing MBLs (IMP-1, Sfh-1, BcII, and GOB-18) and, significantly, an extensively drug-resistant Stenotrophomonas maltophilia clinical isolate expressing L1. BTZs therefore inhibit the full range of MBLs and potentiate β-lactam activity against producer pathogens. X-ray crystal structures reveal insights into diverse BTZ binding modes, varying with orientation of the carboxylate and thiol moieties. BTZs bind the di-zinc centers of B1 (IMP-1; BcII) and B3 (L1) MBLs via the free thiol, but orient differently depending upon stereochemistry. In contrast, the l-BTZ carboxylate dominates interactions with the monozinc B2 MBL Sfh-I, with the thiol uninvolved. d-BTZ complexes most closely resemble β-lactam binding to B1 MBLs, but feature an unprecedented disruption of the D120–zinc interaction. Cross-class MBL inhibition therefore arises from the unexpected versatility of BTZ binding.
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40

Sadowitz, Peter D., Bradley A. Hubbard, James C. Dabrowiak, Jerry Goodisman, Kirk A. Tacka, Mehmet K. Aktas, Mary J. Cunningham, Ronald L. Dubowy, and Abdul-Kader Souid. "Kinetics of Cisplatin Binding to Cellular DNA and Modulations by Thiol-Blocking Agents and Thiol Drugs." Drug Metabolism and Disposition 30, no. 2 (February 1, 2002): 183–90. http://dx.doi.org/10.1124/dmd.30.2.183.

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41

Qian, Yue-Cheng, Peng-Cheng Chen, Xue-Yan Zhu, and Xiao-Jun Huang. "Click synthesis of ionic strength-responsive polyphosphazene hydrogel for reversible binding of enzymes." RSC Advances 5, no. 55 (2015): 44031–40. http://dx.doi.org/10.1039/c5ra06649b.

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42

Paroo, Zain, Michael J. Meredith, Marius Locke, James V. Haist, Morris Karmazyn, and Earl G. Noble. "Redox signaling of cardiac HSF1 DNA binding." American Journal of Physiology-Cell Physiology 283, no. 2 (August 1, 2002): C404—C411. http://dx.doi.org/10.1152/ajpcell.00051.2002.

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Experiments involving chemical induction of the heat shock response in simple biological systems have generated the hypothesis that protein denaturation and consequential binding of heat shock transcription factor 1 (HSF1) to proximal heat shock elements (HSEs) on heat shock protein ( hsp) genes are the result of oxidation and/or depletion of intracellular thiols. The purpose of the present investigation was to determine the role of redox signaling of HSF1 in the intact animal in response to physiological and pharmacological perturbations. Heat shock and exercise induced HSF1-HSE DNA binding in the rat myocardium ( P < 0.001) in the absence of changes in reduced glutathione (GSH), the major nonprotein thiol in the cell. Ischemia-reperfusion, which decreased GSH content ( P < 0.05), resulted in nonsignificant HSF1-HSE formation. This dissociation between physiological induction of HSF1 and changes in GSH was not gender dependent. Pharmacological ablation of GSH withl-buthionine-[ S, R]-sulfoximine (BSO) treatment increased myocardial HSF1-HSE DNA binding in estrogen-naive animals ( P = 0.007). Thus, although physiological induction of HSF1-HSE DNA binding is likely regulated by mediators of protein denaturation other than cellular redox status, the proposed signaling pathway may predominate with pharmacological oxidation and may represent a plausible and accessible strategy in the development of HSP-based therapies.
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43

Chen, C. C., W. J. Guo, and K. J. Isselbacher. "Rat intestinal trehalase. Studies of the active site." Biochemical Journal 247, no. 3 (November 1, 1987): 715–24. http://dx.doi.org/10.1042/bj2470715.

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Rat intestinal trehalase was solubilized, purified and reconstituted into proteoliposomes. With octyl glucoside as the solubilizing detergent, the purified protein appeared as a single band on SDS/polyacrylamide-gel electrophoresis with an apparent molecular mass of 67 kDa. Kinetic studies indicated that the active site of this enzyme can be functionally divided into two adjacent regions, namely a binding site (with pKa 4.8) and a catalytic site (with pKa 7.2). Other findings suggested that the catalytic site contains a functional thiol group, which is sensitive to inhibition by N-ethylmaleimide, Hg2+ and iodoacetate. Substrate protection and iodoacetate labelling of the thiol group demonstrated that only a protein of 67 kDa was labelled. Furthermore, sucrose and phlorizin protected the thiol group, but Tris-like inhibitors did not. Structure-inhibition analysis of Tris-like inhibitors, the pH effect of Tris inhibition and Tris protection of 1-(3-dimethylaminopropyl)-3-ethylcarbodi-imide inactivation permitted characterization and location of a separate site containing a carboxy group for Tris binding, which may also be the binding region. On the basis of these findings, a possible structure for the active site of trehalase is proposed.
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44

Muhammad Arfan, Muhammad Arfan, Sabahat Zahra Siddiqui Sabahat Zahra Siddiqui, Muhammad Athar Abbasi Muhammad Athar Abbasi, Aziz ur Rehman Aziz ur Rehman, Syed Adnan Ali Shah Syed Adnan Ali Shah, Muhammad Ashraf Muhammad Ashraf, Khalid Mohammed Khan Khalid Mohammed Khan, and Rahman Shah Zaib Saleem and Amna Shah Zaib Rahman Shah Zaib Saleem and Amna Shah Zaib. "Synthesis, Spectral Evaluation and in Silico Studies of S-Aralkylated 5-(4-methoxyphenyl)-4-phenyl-4H-1,2,4-triazole-3-thiols: As suitable Alzheimerand#39;s disease drug candidates." Journal of the chemical society of pakistan 43, no. 6 (2021): 694. http://dx.doi.org/10.52568/000974/jcsp/43.06.2021.

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Our efforts lay emphasis on synthesis of S-aralkylated 5-(4-OMeC6H5)-4-phenyl-4H-1,2,4-triazol-3-thiols like pharmacologically active candidates to counter neurodegenerative disorder; Alzheimerand#39;s disease. A synthetic strategy was instigated by esterifying 4-methoxybenzoic acid through Fisher esterificationand#39;s methodology. Hydrazinolysis of corresponding ester was performed under reflux with methanolic hydrated hydrazine to afford 4-methoxybenzohydrazide (I) which refluxing with phenyl isothiocyanate (II) in MeOH to yield a reactive intermediate (III). The later underwent base-catalyzed intermolecular cyclization to furnish 5-(4-OMeC6H5)-4H-1,2,4-triazol-3-thiol (IV). Ultimately, IV was aralkylated at thiol position with aralkyl halides V(a-l) in polar aprotic solvent and catalytic amounts of LiH to provide S-aralkylated 5-(4- OMeC6H5)-4-phenyl-4H-1,2,4-triazol-3-thiols VI(a-l). Modern spectral analysis data explicitly established all the substitutions on nucleophilic S-atom of parent 1,2,4-triazol-3-thiol ring. Effective anti-cholinesterase potential depicted in 3-(phenylpropylthio)-5-(4-OMeC6H5)-4-phenyl-4H-1,2,4-triazole; VIc (IC50; 3.26and#177;0.35 μM) against acetyl cholinesterase; AChE and 3-(phenethylthio)-5-(4-OMeC6H5)-4-phenyl-4H-1,2,4-triazole; VIb (IC50; 8.52and#177;0.54 μM) against butyrylcholinesterase; BChE enzyme as compared to standard Eserine for both enzymes (IC50; 0.04and#177;0.01 μM). Molecular modelling analyses had been conducted to recognize the interconnection of these compounds with enzymes that suggested key interactions (Docking is made to untie the active binding sites). Anti-proliferative activity results showed VIg and VIj with -Cl groups on benzylic ring as promising candidates with HCT-116 cell viability of 14.83 % and 3.09 % respectively.
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45

Lang, John D., Mario Figueroa, Phillip Chumley, Mutay Aslan, John Hurt, Margaret M. Tarpey, Beatriz Alvarez, Rafael Radi, and Bruce A. Freeman. "Albumin and Hydroxyethyl Starch Modulate Oxidative Inflammatory Injury to Vascular Endothelium." Anesthesiology 100, no. 1 (January 1, 2004): 51–58. http://dx.doi.org/10.1097/00000542-200401000-00012.

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Background Human serum albumin is used clinically to maintain colloid osmotic pressure and is viewed to serve an antioxidant role in the vascular compartment via binding of redox-active metal complexes, transport of nitric oxide, and the oxidant-scavenging reactions of the single thiol of human serum albumin, cys34. Because of these potentially desirable adjunctive actions, we evaluated the purity and thiol redox state and compared the relative effects of clinically available 25% human serum albumin preparations with a starch-derived colloid, 6% hydroxyethyl starch, in in vitro models of inflammatory vascular injury. Methods Bovine aortic endothelial cell responses to chemical, enzymatic, and cell-derived reactive inflammatory mediators in the presence of human serum albumin or hydroxyethyl starch were assessed. Results The cys34 thiol of fresh human serum albumin preparations was 70-85% oxidized and contained a population of human serum albumin (approximately 25% of total) having the cys34 resistant to reduction by 2-mercaptoethanol and NaBH4. Treatment of bovine aortic endothelial cells with human serum albumin dose-dependently protected from HOCl-mediated 14C-adenine release, with this protective effect of human serum albumin not dependent on protein thiol status. Addition of human serum albumin to cell media provided no protection from the cytotoxic actions of peroxynitrite and xanthine oxidase-derived reactive species. Binding of activated polymorphonuclear leukocytes to bovine aortic endothelial cells was significantly amplified by hydroxyethyl starch and inhibited by human serum albumin administration. The binding of neutrophil-derived myeloperoxidase to bovine aortic endothelial cells, a mediator of multiple oxidative and nitric oxide-consuming reactions, was also inhibited by human serum albumin and enhanced by hydroxyethyl starch. Conclusions Clinical human serum albumin preparations show modest intrinsic non-thiol-dependent antiinflammatory properties in vitro, a phenomenon that was not observed with hydroxyethyl starch.
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46

Taylor, Neil C., Gary Hessman, Holger B. Kramer, and Joanna F. McGouran. "Probing enzymatic activity – a radical approach." Chemical Science 11, no. 11 (2020): 2967–72. http://dx.doi.org/10.1039/c9sc05258e.

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47

Zucker, Marjorie B., and Evelyn A. Mauss. "Modification of Platelet Functions by Monobromobimane, a Fluorescent Thiol Group Label." Thrombosis and Haemostasis 55, no. 02 (1986): 228–34. http://dx.doi.org/10.1055/s-0038-1661527.

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SummaryMonobromobimane (mBBr, bimane), a compound that penetrates cells and forms a fluorescent adduct with thiol groups, was used to assess the significance of thiols in platelet function. Exposure of washed platelets for 1 min to 100 μM mBBr abolished ADP-induced aggregation; shape change was not inhibited by 500 μM mBBr. The nonpenetrating compound monobromotrimethylammoniobimane was ineffective. Established ADP-induced aggregation was reversed by bimane, and fibrinogen binding to ADP-stimulated platelets was inhibited, an effect mainly due to decreased number of binding sites. Aggregation stimulated by A23187 and arachidonate was less effectively inhibited whereas epinephrine- and collagen-induced aggregation were abolished by 50 μM mBBr. Similar effects on aggregation and secretion were observed in platelet-rich plasma except that higher mBBr concentrations were usually necessary. Aggregation and 14C-serotonin secretion stimulated by 0.1 U/ml thrombin were partially inhibited by pretreatment with bimane. With lower thrombin concentrations, they were often enhanced, as was 3H-arachidonate release. Bimane inhibited epinephrine-induced arachidonate release in gel-filtered platelets, possibly because it abolished the primary aggregation necessary for this release. mBBr did not elevate cyclic AMP but enhanced the increase induced by PGEi and prevented the subsequent decrease typically caused by ADP. Examination of SDS polyacrylamide gels with ultraviolet light showed that mBBr reacted with many platelet proteins but not with GP lib or Ilia. This observation, and the fact that bimane did not inhibit the fibrinogen-induced aggregation of DTT- or chymotrypsin-treated platelets suggest that it reacts with thiol group(s) that are involved in “exposing” the fibrinogen receptor.
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48

López, María I., Dolores Esquivel, César Jiménez-Sanchidrián, Pascal Van Der Voort, and Francisco J. Romero-Salguero. "Thiol-Functionalized Ethylene Periodic Mesoporous Organosilica as an Efficient Scavenger for Palladium: Confirming the Homogeneous Character of the Suzuki Reaction." Materials 13, no. 3 (January 30, 2020): 623. http://dx.doi.org/10.3390/ma13030623.

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This work describes the synthesis of thiol-functionalized periodic mesoporous organosilicas (PMOs) prepared using the precursor 1-thiol-1,2-bis(triethoxysilyl)ethane, alone or mixed with 1,2-bis(triethoxysilyl)ethane. The thiol groups incorporated into the structure were found to be efficient for palladium binding. This has allowed these materials to be used as catalysts in the Suzuki cross-coupling reaction of bromobenzene and phenylboronic acid. Their performance has been compared to palladium-supported periodic mesoporous (organo)silicas and important differences have been observed between them. The use of different heterogeneity tests, such as hot filtration test and poisoning experiments, has provided a deep insight into the reaction mechanism and has confirmed that the reaction occurs in the homogeneous phase following a “release and catch” mechanism. Furthermore, the thiol-functionalized periodic mesoporous organosilica, synthesized using only 1-thiol-1,2-bis(triethoxysilyl)ethane as a precursor, has proven to be an efficient palladium scavenger.
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49

Zumbrennen, Kimberly B., Michelle L. Wallander, S. Joshua Romney, and Elizabeth A. Leibold. "Cysteine Oxidation Regulates the RNA-Binding Activity of Iron Regulatory Protein 2." Molecular and Cellular Biology 29, no. 8 (February 17, 2009): 2219–29. http://dx.doi.org/10.1128/mcb.00004-09.

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ABSTRACT Iron regulatory protein 2 (IRP2) is an RNA-binding protein that regulates the posttranscriptional expression of proteins required for iron homeostasis such as ferritin and transferrin receptor 1. IRP2 RNA-binding activity is primarily regulated by iron-mediated proteasomal degradation, but studies have suggested that IRP2 RNA binding is also regulated by thiol oxidation. We generated a model of IRP2 bound to RNA and found that two cysteines (C512 and C516) are predicted to lie in the RNA-binding cleft. Site-directed mutagenesis and thiol modification show that, while IRP2 C512 and C516 do not directly interact with RNA, both cysteines are located within the RNA-binding cleft and must be unmodified/reduced for IRP2-RNA interactions. Oxidative stress induced by cellular glucose deprivation reduces the RNA-binding activity of IRP2 but not IRP2-C512S or IRP2-C516S, consistent with the formation of a disulfide bond between IRP2 C512 and C516 during oxidative stress. Decreased IRP2 RNA binding is correlated with reduced transferrin receptor 1 mRNA abundance. These studies provide insight into the structural basis for IRP2-RNA interactions and reveal an iron-independent mechanism for regulating iron homeostasis through the redox regulation of IRP2 cysteines.
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Laroussi, Arwa, Małgorzata Kot, Jan Ingo Flege, Noureddine Raouafi, and Vladimir Mirsky. "Self-Assembled Monolayers from Symmetrical Di-Thiols: Preparation, Characterization and Application for the Assembly of Electrochemically Active Films." Engineering Proceedings 6, no. 1 (May 17, 2021): 17. http://dx.doi.org/10.3390/i3s2021dresden-10112.

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1,3-dimercaptopropan-2-ol, a symmetrical di-thiol, has been synthesized and applied as a new type of anchor molecule to prepare a self-assembled monolayer (SAM) on a gold surface. The formed monolayers were studied by cyclic voltammetry, impedance spectroscopy, X-ray photoelectron spectroscopy, kinetic capacitance, and contact angle measurements. The SAM structure depends on the adsorption conditions. A short incubation time of the electrode at high concentration of this di-thiol leads to the predominating binding through one thiol group of the adsorbate to the gold surface, while a long incubation at low concentration leads to the predominating binding by both thiol groups. A comparative study of the desorption and replacement of SAMs indicates a strong stability increase when the SAM molecules bond gold surfaces by two bonds mainly. This monolayer was used to immobilize electrochemically active p-benzoquinone moiety. The surface concentration of p-benzoquinone obtained from cyclic voltammetry is 2.5 ± 0.2 × 10−10 mol cm−2, which corresponds to the functionalization of 65 ± 5% of SAM molecules. The obtained highly stable SAM with redox-active terminal group can be applied for different tasks of chemical sensing and biosensing. As an example, an application of this system for electrocatalytical oxidation of dihydronicotinamide adenosine dinucleotide (NADH) was tested.
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