Статті в журналах: "Sulfur Peptide"

1

Rademann, Jörg, Ahsanullah Ahsanullah, Abbas Hassan, and Farzana L. Ansari. "Integration of C-Acylation in the Solid-Phase Synthesis of Peptides and Peptidomimetics Employing Meldrum’s Acid, Phosphorus, and Sulfur Ylides." Synthesis 54, no. 06 (October 12, 2021): 1503–17. http://dx.doi.org/10.1055/a-1667-3648.

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AbstractThe modification of native peptides to peptidomimetics is an important goal in medicinal chemistry and requires, in many cases, the integration of C-acylation steps involving amino acids with classical peptide synthesis. Many classical C-acylation protocols involving Claisen condensations and the use of ylides are not compatible with peptide synthesis, mostly due to the requirements for strong bases leading to epimerization or deprotection of peptides. Meldrum’s acid as well as several specific phosphorus and sulfur ylides, however, are acidic enough to provide reactive C-nucleophiles under mildly basic conditions tolerated during peptide synthesis. This review provides an overview of peptide-compatible C-acylations using Meldrum’s acid and phosphorus and sulfur ylides, and their application in the medicinal chemistry of peptides.1 Introduction2 C-Acylation of Meldrum’s Acid2.1 C-Acylation of Meldrum’s Acid on Solid Phase3 Ylides as Substrates for C-Acylation3.1 C-Acylation of Phosphorus Ylides in Solution Phase3.2 C-Acylation of Solid-Supported Phosphorus Ylides3.3 C-Acylation of Sulfur Ylides3.4 C-Acylation of Solid-Supported Sulfur Ylides4 Miscellaneous Ylides as Acyl Anion Equivalents5 Summary

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2

Neugebauer, W. J., and E. Escher. "Peptide labelling with sulfur-35." International Journal of Radiation Applications and Instrumentation. Part A. Applied Radiation and Isotopes 39, no. 6 (January 1988): 539. http://dx.doi.org/10.1016/0883-2889(88)90255-9.

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3

Adams, Michael W. W., James F. Holden, Angeli Lal Menon, Gerrit J. Schut, Amy M. Grunden, Chun Hou, Andrea M. Hutchins, et al. "Key Role for Sulfur in Peptide Metabolism and in Regulation of Three Hydrogenases in the Hyperthermophilic ArchaeonPyrococcus furiosus." Journal of Bacteriology 183, no. 2 (January 15, 2001): 716–24. http://dx.doi.org/10.1128/jb.183.2.716-724.2001.

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ABSTRACT The hyperthermophilic archaeon Pyrococcus furiosusgrows optimally at 100°C by the fermentation of peptides and carbohydrates. Growth of the organism was examined in media containing either maltose, peptides (hydrolyzed casein), or both as the carbon source(s), each with and without elemental sulfur (S0). Growth rates were highest on media containing peptides and S0, with or without maltose. Growth did not occur on the peptide medium without S0. S0 had no effect on growth rates in the maltose medium in the absence of peptides. Phenylacetate production rates (from phenylalanine fermentation) from cells grown in the peptide medium containing S0 with or without maltose were the same, suggesting that S0 is required for peptide utilization. The activities of 14 of 21 enzymes involved in or related to the fermentation pathways of P. furiosus were shown to be regulated under the five different growth conditions studied. The presence of S0 in the growth media resulted in decreases in specific activities of two cytoplasmic hydrogenases (I and II) and of a membrane-bound hydrogenase, each by an order of magnitude. The primary S0-reducing enzyme in this organism and the mechanism of the S0 dependence of peptide metabolism are not known. This study provides the first evidence for a highly regulated fermentation-based metabolism in P. furiosus and a significant regulatory role for elemental sulfur or its metabolites.

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4

Kaufmann, Christine, and Margret Sauter. "Sulfated plant peptide hormones." Journal of Experimental Botany 70, no. 16 (June 20, 2019): 4267–77. http://dx.doi.org/10.1093/jxb/erz292.

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Abstract Sulfated peptides are plant hormones that are active at nanomolar concentrations. The sulfation at one or more tyrosine residues is catalysed by tyrosylprotein sulfotransferase (TPST), which is encoded by a single-copy gene. The sulfate group is provided by the co-substrate 3´-phosphoadenosine 5´-phosphosulfate (PAPS), which links synthesis of sulfated signaling peptides to sulfur metabolism. The precursor proteins share a conserved DY-motif that is implicated in specifying tyrosine sulfation. Several sulfated peptides undergo additional modification such as hydroxylation of proline and glycosylation of hydroxyproline. The modifications render the secreted signaling molecules active and stable. Several sulfated signaling peptides have been shown to be perceived by leucine-rich repeat receptor-like kinases (LRR-RLKs) but have signaling pathways that, for the most part, are yet to be elucidated. Sulfated peptide hormones regulate growth and a wide variety of developmental processes, and intricately modulate immunity to pathogens. While basic research on sulfated peptides has made steady progress, their potential in agricultural and pharmaceutical applications has yet to be explored.

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5

Francioso, Antonio, Alessia Baseggio Conrado, Carla Blarzino, Cesira Foppoli, Elita Montanari, Simone Dinarelli, Alessandra Giorgi, Luciana Mosca та Mario Fontana. "One- and Two-Electron Oxidations of β-Amyloid25-35 by Carbonate Radical Anion (CO3•−) and Peroxymonocarbonate (HCO4−): Role of Sulfur in Radical Reactions and Peptide Aggregation". Molecules 25, № 4 (20 лютого 2020): 961. http://dx.doi.org/10.3390/molecules25040961.

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The β-amyloid (Aβ) peptide plays a key role in the pathogenesis of Alzheimer’s disease. The methionine (Met) residue at position 35 in Aβ C-terminal domain is critical for neurotoxicity, aggregation, and free radical formation initiated by the peptide. The role of Met in modulating toxicological properties of Aβ most likely involves an oxidative event at the sulfur atom. We therefore investigated the one- or two-electron oxidation of the Met residue of Aβ25-35 fragment and the effect of such oxidation on the behavior of the peptide. Bicarbonate promotes two-electron oxidations mediated by hydrogen peroxide after generation of peroxymonocarbonate (HCO4−, PMC). The bicarbonate/carbon dioxide pair stimulates one-electron oxidations mediated by carbonate radical anion (CO3•−). PMC efficiently oxidizes thioether sulfur of the Met residue to sulfoxide. Interestingly, such oxidation hampers the tendency of Aβ to aggregate. Conversely, CO3•− causes the one-electron oxidation of methionine residue to sulfur radical cation (MetS•+). The formation of this transient reactive intermediate during Aβ oxidation may play an important role in the process underlying amyloid neurotoxicity and free radical generation.

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6

Prütz, Walter A., John Butler, Edward J. Land, and A. John Swallow. "Unpaired Electron Migration between Aromatic and Sulfur Peptide Units." Free Radical Research Communications 2, no. 1-2 (January 1986): 69–75. http://dx.doi.org/10.3109/10715768609088056.

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7

Kosted, Paula J., Shirley A. Gerhardt, and John E. Sherwood. "Pheromone-Related Inhibitors of Ustilago hordei Mating and Tilletia tritici Teliospore Germination." Phytopathology® 92, no. 2 (February 2002): 210–16. http://dx.doi.org/10.1094/phyto.2002.92.2.210.

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Ustilago hordei, the causal agent of barley covered smut, produces mating pheromones that break down to smaller peptide compounds that act as potent inhibitors of mating and germination in several fungi. The pheromones are members of the farnesylated family of proteins. Synthetic peptide analogs of the pheromone derivatives, ranging in size from 4 mers to full length pheromones, were farnesylated, methyl esterified, or both and tested for mating or teliospore germination inhibition with U. hordei or Tilletia tritici, respectively. N-Acetyl-S-farnesylcysteine, which inhibits processing of Ras, and other sulfur-containing compounds such as homocysteine or methionine, were likewise modified and tested. The most potent inhibitors were methionine methyl ester and modified 4-mer peptides from both pheromones. Alanine scanning of the inhibitory 4 mers determined that the native amino acid sequence was specific for a high level of activity. The sulfur amino acids appear to be required for inhibition. Glasshouse studies using selected antagonists of mating and teliospore germination as seed treatments inhibited covered smut of barley and common bunt of wheat, although the level of control was inconsistent. The use of pheromone-related antagonists to mating or teliospore germination is a promising, novel strategy for control of smut and bunt diseases.

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8

Abe, Tomoko, Yoshiteru Hashimoto, Ye Zhuang, Yin Ge, Takuto Kumano, and Michihiko Kobayashi. "Peptide Bond Synthesis by a Mechanism Involving an Enzymatic Reaction and a Subsequent Chemical Reaction." Journal of Biological Chemistry 291, no. 4 (November 19, 2015): 1735–50. http://dx.doi.org/10.1074/jbc.m115.700989.

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We recently reported that an amide bond is unexpectedly formed by an acyl-CoA synthetase (which catalyzes the formation of a carbon-sulfur bond) when a suitable acid and l-cysteine are used as substrates. DltA, which is homologous to the adenylation domain of nonribosomal peptide synthetase, belongs to the same superfamily of adenylate-forming enzymes, which includes many kinds of enzymes, including the acyl-CoA synthetases. Here, we demonstrate that DltA synthesizes not only N-(d-alanyl)-l-cysteine (a dipeptide) but also various oligopeptides. We propose that this enzyme catalyzes peptide synthesis by the following unprecedented mechanism: (i) the formation of S-acyl-l-cysteine as an intermediate via its “enzymatic activity” and (ii) subsequent “chemical” S → N acyl transfer in the intermediate, resulting in peptide formation. Step ii is identical to the corresponding reaction in native chemical ligation, a method of chemical peptide synthesis, whereas step i is not. To the best of our knowledge, our discovery of this peptide synthesis mechanism involving an enzymatic reaction and a subsequent chemical reaction is the first such one to be reported. This new process yields peptides without the use of a thioesterified fragment, which is required in native chemical ligation. Together with these findings, the same mechanism-dependent formation of N-acyl compounds by other members of the above-mentioned superfamily demonstrated that all members most likely form peptide/amide compounds by using this novel mechanism. Each member enzyme acts on a specific substrate; thus, not only the corresponding peptides but also new types of amide compounds can be formed.

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9

Keegan, Brenna C., Daniel Ocampo, and Jason Shearer. "pH Dependent Reversible Formation of a Binuclear Ni2 Metal-Center within a Peptide Scaffold." Inorganics 7, no. 7 (July 16, 2019): 90. http://dx.doi.org/10.3390/inorganics7070090.

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A disulfide-bridged peptide containing two Ni2+ binding sites based on the nickel superoxide dismutase protein, {Ni2(SODmds)} has been prepared. At physiological pH (7.4), it was found that the metal sites are mononuclear with a square planar NOS2 coordination environment with the two sulfur-based ligands derived from cysteinate residues, the nitrogen ligand derived from the amide backbone, and a water ligand. Furthermore, S K-edge X-ray absorption spectroscopy indicated that the two cysteinate sulfur atoms ligated to nickel are each protonated. Elevation of the pH to 9.6 results in the deprotonation of the cysteinate sulfur atoms, and yields a binuclear, cysteinate bridged Ni22+ center with each nickel contained in a distorted square planar geometry. At both pH = 7.4 and 9.6, the nickel sites are moderately air sensitive, yielding intractable oxidation products. However, at pH = 9.6, {Ni2(SODmds)} reacts with O2 at an ~3.5-fold faster rate than at pH = 7.4. Electronic structure calculations indicate that the reduced reactivity at pH = 7.4 is a result of a reduction in S(3p) character and deactivation of the nucleophilic frontier molecular orbitals upon cysteinate sulfur protonation.

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10

Zeng, Xiang, Xiaobo Zhang, and Zongze Shao. "Metabolic Adaptation to Sulfur of Hyperthermophilic Palaeococcus pacificus DY20341T from Deep-Sea Hydrothermal Sediments." International Journal of Molecular Sciences 21, no. 1 (January 6, 2020): 368. http://dx.doi.org/10.3390/ijms21010368.

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The hyperthermo-piezophilic archaeon Palaeococcus pacificus DY20341T, isolated from East Pacific hydrothermal sediments, can utilize elemental sulfur as a terminal acceptor to simulate growth. To gain insight into sulfur metabolism, we performed a genomic and transcriptional analysis of Pa. pacificus DY20341T with/without elemental sulfur as an electron acceptor. In the 2001 protein-coding sequences of the genome, transcriptomic analysis showed that 108 genes increased (by up to 75.1 fold) and 336 genes decreased (by up to 13.9 fold) in the presence of elemental sulfur. Palaeococcus pacificus cultured with elemental sulfur promoted the following: the induction of membrane-bound hydrogenase (MBX), NADH:polysulfide oxidoreductase (NPSOR), NAD(P)H sulfur oxidoreductase (Nsr), sulfide dehydrogenase (SuDH), connected to the sulfur-reducing process, the upregulation of iron and nickel/cobalt transfer, iron–sulfur cluster-carrying proteins (NBP35), and some iron–sulfur cluster-containing proteins (SipA, SAM, CobQ, etc.). The accumulation of metal ions might further impact on regulators, e.g., SurR and TrmB. For growth in proteinous media without elemental sulfur, cells promoted flagelin, peptide/amino acids transporters, and maltose/sugar transporters to upregulate protein and starch/sugar utilization processes and riboflavin and thiamin biosynthesis. This indicates how strain DY20341T can adapt to different living conditions with/without elemental sulfur in the hydrothermal fields.

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11

Wang, Wenji, Cong Zhao, Dengsen Zhu, Gehui Gong, and Weihong Du. "Inhibition of amyloid peptide fibril formation by gold–sulfur complexes." Journal of Inorganic Biochemistry 171 (June 2017): 1–9. http://dx.doi.org/10.1016/j.jinorgbio.2017.02.021.

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12

Wiles, Amy M., Houjian Cai, Fred Naider, and Jeffrey M. Becker. "Nutrient regulation of oligopeptide transport in Saccharomyces cerevisiae." Microbiology 152, no. 10 (October 1, 2006): 3133–45. http://dx.doi.org/10.1099/mic.0.29055-0.

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Small peptides (2–5 amino acid residues) are transported into Saccharomyces cerevisiae via two transport systems: PTR (Peptide TRansport) for di-/tripeptides and OPT (OligoPeptide Transport) for oligopeptides of 4–5 amino acids in length. Although regulation of the PTR system has been studied in some detail, neither the regulation of the OPT family nor the environmental conditions under which family members are normally expressed have been well studied in S. cerevisiae. Using a lacZ reporter gene construct fused to 1 kb DNA from upstream of the genes OPT1 and OPT2, which encode the two S. cerevisiae oligopeptide transporters, the relative expression levels of these genes were measured in a variety of environmental conditions. Uptake assays were also conducted to measure functional protein levels at the plasma membrane. It was found that OPT1 was up-regulated in sulfur-free medium, and that Ptr3p and Ssy1p, proteins involved in regulating the di-/tripeptide transporter encoding gene PTR2 via amino acid sensing, were required for OPT1 expression in a sulfur-free environment. In contrast, as measured by response to toxic tetrapeptide and by real-time PCR, OPT1 was not regulated through Cup9p, which is a repressor for PTR2 expression, although Cup9p did repress OPT2 expression. In addition, all of the 20 naturally occurring amino acids, except the sulfur-containing amino acids methionine and cysteine, up-regulated OPT1, with the greatest change in expression observed when cells were grown in sulfur-free medium. These data demonstrate that regulation of the OPT system has both similarities and differences to regulation of the PTR system, allowing the yeast cell to adapt its utilization of small peptides to various environmental conditions.

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13

Djuran, Milo I., and Snezana U. Milinkovic´. "1H N.M.R. investigations of the selective intramolecular migration of a platinum(II) complex from methionine sulfur to imidazole N 1 in N-acetylated L-methionyl-L-histidine." Australian Journal of Chemistry 53, no. 8 (2000): 645. http://dx.doi.org/10.1071/ch00065.

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Reactions of two platinum(II) complexes [Pt(dien)Cl]+ and [Pt(Gly-Met-S,N,N´)Cl], in which dien is diethylenetriamine and Gly-Met is the dipeptide glycyl-L-methionine coordinated through the sulfur and two nitrogen atoms, with N-acetylated dipeptide L-methionyl-L-histidine (MeCO-Met-His) have been studied by 1H n.m.r. spectroscopy. All reactions were carried out in 50 mM phosphate buffer at pD 7.4 and at room temperature. In the initial stages of the reactions both platinum(II) complexes form a kinetically favoured platinum–peptide complex with unidentate coordination of MeCO-Met-His through the sulfur atom of the methionine residue. In the second stages of the reaction an intramolecular migration of a [Pt(dien)]2+ unit from the sulfur to the nitrogen atom of imidazole has been observed. This migration reaction is very slow and strongly selective to the N 1 atom of the imidazole ring of the histidine side chain. No migration of the platinum(II) complex was observed in the reaction between [Pt(Gly-Met-S,N,N´)Cl] and the dipeptide MeCO-Met-His. It was found that the latter complex, with a more sterically hindered Gly-Met ligand, reacts more slowly with thioether-containing molecules than [Pt(dien)Cl]+ and forms a more stable platinum–sulfur bond. This study is an important step in the development of new platinum(II) complexes for selective covalent modification of peptides and proteins.

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14

del Rı́o, José C., M. A. Olivella, Heike Knicker, and F. Xavier C. de las Heras. "Preservation of peptide moieties in three Spanish sulfur-rich Tertiary kerogens." Organic Geochemistry 35, no. 9 (September 2004): 993–99. http://dx.doi.org/10.1016/j.orggeochem.2004.06.002.

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15

Kato, Katsuya, Sungho Lee, and Fukue Nagata. "Preparation of Protein–Peptide–Calcium Phosphate Composites for Controlled Protein Release." Molecules 25, no. 10 (May 14, 2020): 2312. http://dx.doi.org/10.3390/molecules25102312.

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Protein–peptide–calcium phosphate composites were developed for achieving sustainable and controlled protein release. Bovine serum albumin (BSA) as a model acidic protein was efficiently encapsulated with basic polypeptides such as polylysine and polyarginine during the precipitation of calcium phosphate (CaP). The prepared composites were fully characterized in terms of their morphologies, crystallinities, and the porosity of their structures, and from these analyses, it was observed that there are no significant differences between the composites. Scanning transmission electron microscopy and energy dispersive X-ray spectroscopy analysis indicated a homogeneous distribution of nitrogen and sulfur, confirming the uniform distribution of BSA and polypeptide in the CaP composite. In vitro release studies demonstrated that the composite prepared with the peptides α-polylysine and polyarginine were suitable for the gradual release of the protein BSA, while those containing ε-polylysine and no peptide were unsuitable for protein release. Additionally, these composites showed high hemocompatibility for mouse red blood cells, and the osteoblast-like cell proliferation and spread in media with the composites prepared using BSA and α-polylysine showed similar tendencies to medium with no composite. From these results, protein–peptide–CaP composites are expected to be useful as highly biocompatible protein delivery agents.

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16

McLaughlin, Martin I., Nicholas D. Lanz, Peter J. Goldman, Kyung-Hoon Lee, Squire J. Booker, and Catherine L. Drennan. "Crystallographic snapshots of sulfur insertion by lipoyl synthase." Proceedings of the National Academy of Sciences 113, no. 34 (August 9, 2016): 9446–50. http://dx.doi.org/10.1073/pnas.1602486113.

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Lipoyl synthase (LipA) catalyzes the insertion of two sulfur atoms at the unactivated C6 and C8 positions of a protein-bound octanoyl chain to produce the lipoyl cofactor. To activate its substrate for sulfur insertion, LipA uses a [4Fe-4S] cluster and S-adenosylmethionine (AdoMet) radical chemistry; the remainder of the reaction mechanism, especially the source of the sulfur, has been less clear. One controversial proposal involves the removal of sulfur from a second (auxiliary) [4Fe-4S] cluster on the enzyme, resulting in destruction of the cluster during each round of catalysis. Here, we present two high-resolution crystal structures of LipA from Mycobacterium tuberculosis: one in its resting state and one at an intermediate state during turnover. In the resting state, an auxiliary [4Fe-4S] cluster has an unusual serine ligation to one of the irons. After reaction with an octanoyllysine-containing 8-mer peptide substrate and 1 eq AdoMet, conditions that allow for the first sulfur insertion but not the second insertion, the serine ligand dissociates from the cluster, the iron ion is lost, and a sulfur atom that is still part of the cluster becomes covalently attached to C6 of the octanoyl substrate. This intermediate structure provides a clear picture of iron–sulfur cluster destruction in action, supporting the role of the auxiliary cluster as the sulfur source in the LipA reaction and describing a radical strategy for sulfur incorporation into completely unactivated substrates.

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17

Rother, Dagmar, Hans-Jürgen Henrich, Armin Quentmeier, Frank Bardischewsky, and Cornelius G. Friedrich. "Novel Genes of the sox Gene Cluster, Mutagenesis of the Flavoprotein SoxF, and Evidence for a General Sulfur-Oxidizing System in Paracoccus pantotrophusGB17." Journal of Bacteriology 183, no. 15 (August 1, 2001): 4499–508. http://dx.doi.org/10.1128/jb.183.15.4499-4508.2001.

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ABSTRACT The novel genes soxFGH were identified, completing the sox gene cluster of Paracoccus pantotrophus coding for enzymes involved in lithotrophic sulfur oxidation. The periplasmic SoxF, SoxG, and SoxH proteins were induced by thiosulfate and purified to homogeneity from the soluble fraction.soxF coded for a protein of 420 amino acids with a signal peptide containing a twin-arginine motif. SoxF was 37% identical to the flavoprotein FccB of flavocytochrome csulfide dehydrogenase of Allochromatium vinosum. The mature SoxF (42,832 Da) contained 0.74 mol of flavin adenine dinucleotide per mol. soxG coded for a novel protein of 303 amino acids with a signal peptide containing a twin-arginine motif. The mature SoxG (29,657 Da) contained two zinc binding motifs and 0.90 atom of zinc per subunit of the homodimer. soxH coded for a periplasmic protein of 317 amino acids with a double-arginine signal peptide. The mature SoxH (32,317 Da) contained two metal binding motifs and 0.29 atom of zinc and 0.20 atom of copper per subunit of the homodimer. SoxXA, SoxYZ, SoxB, and SoxCD (C. G. Friedrich, A. Quentmeier, F. Bardischewsky, D. Rother, R. Kraft, S. Kostka, and H. Prinz, J. Bacteriol. 182:4476–4487, 2000) reconstitute a system able to perform thiosulfate-, sulfite-, sulfur-, and hydrogen sulfide-dependent cytochrome c reduction, and this system is the first described for oxidizing different inorganic sulfur compounds. SoxF slightly inhibited the rate of hydrogen sulfide oxidation but not the rate of sulfite or thiosulfate oxidation. From use of a homogenote mutant with an in-frame deletion insoxF and complementation analysis, it was evident that the soxFGH gene products were not required for lithotrophic growth with thiosulfate.

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18

Zyla, Edyta, Bogdan Musielak, Tad A. Holak, and Grzegorz Dubin. "Structural Characterization of a Macrocyclic Peptide Modulator of the PD-1/PD-L1 Immune Checkpoint Axis." Molecules 26, no. 16 (August 11, 2021): 4848. http://dx.doi.org/10.3390/molecules26164848.

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The clinical success of PD-1/PD-L1 immune checkpoint targeting antibodies in cancer is followed by efforts to develop small molecule inhibitors with better penetration into solid tumors and more favorable pharmacokinetics. Here we report the crystal structure of a macrocyclic peptide inhibitor (peptide 104) in complex with PD-L1. Our structure shows no indication of an unusual bifurcated binding mode demonstrated earlier for another peptide of the same family (peptide 101). The binding mode relies on extensive hydrophobic interactions at the center of the binding surface and an electrostatic patch at the side. An interesting sulfur/π interaction supports the macrocycle-receptor binding. Overall, our results allow a better understanding of forces guiding macrocycle affinity for PD-L1, providing a rationale for future structure-based inhibitor design and rational optimization.

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19

Farnaud, Sébastien, Chiara Rapisarda, Tam Bui, Alex Drake, Richard Cammack, and Robert W. Evans. "Identification of an iron–hepcidin complex." Biochemical Journal 413, no. 3 (July 15, 2008): 553–57. http://dx.doi.org/10.1042/bj20080406.

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Following its identification as a liver-expressed antimicrobial peptide, the hepcidin peptide was later shown to be a key player in iron homoeostasis. It is now proposed to be the ‘iron hormone’ which, by interacting with the iron transporter ferroportin, prevents further iron import into the circulatory system. This conclusion was reached using the corresponding synthetic peptide, emphasizing the functional importance of the mature 25-mer peptide, but omitting the possible functionality of its maturation. From urine-purified native hepcidin, we recently demonstrated that a proportion of the purified hepcidin had formed iron–hepcidin complexes. This interaction was investigated further by computer modelling and, based on the sequence similarity of hepcidin with metallothionein, a three-dimensional model of hepcidin, containing one atom of iron, was constructed. To characterize these complexes further, the interaction with iron was analysed using different spectroscopic methods. Monoferric hepcidin was identified by MS, as were possibly other complexes containing two and three atoms of iron respectively, although these were present only in minor amounts. UV/visible absorbance and CD studies identified the iron-binding events which were facilitated at a physiological pH. EPR spectroscopy identified the ferric state of the bound metal, and indicated that the iron–hepcidin complex shares some similarities with the rubredoxin iron–sulfur complex, suggesting the presence of Fe3+ in a tetrahedral sulfur co-ordination. The potential roles of iron binding for hepcidin are discussed, and we propose either a regulatory function in the maturation of pro-hepcidin into active hepcidin or as the necessary link in the interaction between hepcidin and ferroportin.

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20

Liao, Yanyan, and Xuefeng Jiang. "Construction of Thioamide Peptide via Sulfur-Involved Amino Acids/Amino Aldehydes Coupling." Organic Letters 23, no. 22 (November 11, 2021): 8862–66. http://dx.doi.org/10.1021/acs.orglett.1c03370.

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21

NOORT, D., E. H. JACOBS, A. FIDDER, L. P. A. JONG, J. W. DRIJFHOUT, and H. P. BENSCHOP. "Solid-phase synthesis of peptide haptens containing a cysteine-sulfur mustard adduct." International Journal of Peptide and Protein Research 45, no. 6 (January 12, 2009): 497–500. http://dx.doi.org/10.1111/j.1399-3011.1995.tb01311.x.

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22

Sauvé, Véronique, Stefano Bruno, Ben C. Berks, and Andrew M. Hemmings. "The SoxYZ Complex Carries Sulfur Cycle Intermediates on a Peptide Swinging Arm." Journal of Biological Chemistry 282, no. 32 (May 23, 2007): 23194–204. http://dx.doi.org/10.1074/jbc.m701602200.

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23

Sommer, Dayn Joseph, Anindya Roy, Andrei Astashkin, and Giovanna Ghirlanda. "Modulation of cluster incorporation specificity in ade novoiron-sulfur cluster binding peptide." Biopolymers 104, no. 4 (July 2015): 412–18. http://dx.doi.org/10.1002/bip.22635.

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24

Chatgilialoglu, Chryssostomos, Magdalena Grzelak, Konrad Skotnicki, Piotr Filipiak, Franciszek Kazmierczak, Gordon L. Hug, Krzysztof Bobrowski, and Bronislaw Marciniak. "Evaluation of Hydroxyl Radical Reactivity by Thioether Group Proximity in Model Peptide Backbone: Methionine versus S-Methyl-Cysteine." International Journal of Molecular Sciences 23, no. 12 (June 11, 2022): 6550. http://dx.doi.org/10.3390/ijms23126550.

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Hydroxyl radicals (HO•) have long been regarded as a major source of cellular damage. The reaction of HO• with methionine residues (Met) in peptides and proteins is a complex multistep process. Although the reaction mechanism has been intensively studied, some essential parts remain unsolved. In the present study we examined the reaction of HO• generated by ionizing radiation in aqueous solutions under anoxic conditions with two compounds representing the simplest model peptide backbone CH3C(O)NHCHXC(O)NHCH3, where X = CH2CH2SCH3 or CH2SCH3, i.e., the Met derivative in comparison with the cysteine-methylated derivative. We performed the identification and quantification of transient species by pulse radiolysis and final products by LC–MS and high-resolution MS/MS after γ-radiolysis. The results allowed us to draw for each compound a mechanistic scheme. The fate of the initial one-electron oxidation at the sulfur atom depends on its distance from the peptide backbone and involves transient species of five-membered and/or six-membered ring formations with different heteroatoms present in the backbone as well as quite different rates of deprotonation in forming α-(alkylthio)alkyl radicals.

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25

Forquin, Marie-Pierre, Agnès Hébert, Aurélie Roux, Julie Aubert, Caroline Proux, Jean-François Heilier, Sophie Landaud, Christophe Junot, Pascal Bonnarme, and Isabelle Martin-Verstraete. "Global Regulation of the Response to Sulfur Availability in the Cheese-Related BacteriumBrevibacterium aurantiacum." Applied and Environmental Microbiology 77, no. 4 (December 17, 2010): 1449–59. http://dx.doi.org/10.1128/aem.01708-10.

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ABSTRACTIn this study, we combined metabolic reconstruction, growth assays, and metabolome and transcriptome analyses to obtain a global view of the sulfur metabolic network and of the response to sulfur availability inBrevibacterium aurantiacum. In agreement with the growth ofB. aurantiacumin the presence of sulfate and cystine, the metabolic reconstruction showed the presence of a sulfate assimilation pathway, thiolation pathways that produce cysteine (cysEandcysK) or homocysteine (metXandmetY) from sulfide, at least one gene of the transsulfuration pathway (aecD), and genes encoding three MetE-type methionine synthases. We also compared the expression profiles ofB. aurantiacumATCC 9175 during sulfur starvation or in the presence of sulfate. Under sulfur starvation, 690 genes, including 21 genes involved in sulfur metabolism and 29 genes encoding amino acids and peptide transporters, were differentially expressed. We also investigated changes in pools of sulfur-containing metabolites and in expression profiles after growth in the presence of sulfate, cystine, or methionine plus cystine. The expression of genes involved in sulfate assimilation and cysteine synthesis was repressed in the presence of cystine, whereas the expression ofmetX,metY,metE1,metE2, andBL613, encoding a probable cystathionine-γ-synthase, decreased in the presence of methionine. We identified three ABC transporters: two operons encoding transporters were transcribed more strongly during cysteine limitation, and one was transcribed more strongly during methionine depletion. Finally, the expression of genes encoding a methionine γ-lyase (BL929) and a methionine transporter (metPS) was induced in the presence of methionine in conjunction with a significant increase in volatile sulfur compound production.

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26

Dong, Wei, Yinghua Wang, and Hideki Takahashi. "CLE-CLAVATA1 Signaling Pathway Modulates Lateral Root Development under Sulfur Deficiency." Plants 8, no. 4 (April 18, 2019): 103. http://dx.doi.org/10.3390/plants8040103.

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Plant root system architecture changes drastically in response to availability of macronutrients in the soil environment. Despite the importance of root sulfur (S) uptake in plant growth and reproduction, molecular mechanisms underlying root development in response to S availability have not been fully characterized. We report here on the signaling module composed of the CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION (CLE) peptide and CLAVATA1 (CLV1) leucine-rich repeat receptor kinase, which regulate lateral root (LR) development in Arabidopsis thaliana upon changes in S availability. The wild-type seedlings exposed to prolonged S deficiency showed a phenotype with low LR density, which was restored upon sulfate supply. In contrast, the clv1 mutant showed a higher daily increase rate of LR density relative to the wild-type under prolonged S deficiency, which was diminished to the wild-type level upon sulfate supply, suggesting that CLV1 directs a signal to inhibit LR development under S-deficient conditions. CLE2 and CLE3 transcript levels decreased under S deficiency and through CLV1-mediated feedback regulations, suggesting the levels of CLE peptide signals are adjusted during the course of LR development. This study demonstrates a fine-tuned mechanism for LR development coordinately regulated by CLE-CLV1 signaling and in response to changes in S availability.

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27

Weese-Myers, Moriah E., and Ashley E. Ross. "Characterization of Electroactive Amino Acids with Fast-Scan Cyclic Voltammetry." Journal of The Electrochemical Society 168, no. 12 (December 1, 2021): 126524. http://dx.doi.org/10.1149/1945-7111/ac4187.

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Small molecules and signaling peptides are extensively involved in controlling basic brain function. While classical neurotransmitters can be detected with a variety of techniques, methods for measurement of rapidly-released neuropeptides remain underdeveloped. Fast-scan cyclic voltammetry (FSCV) is an electrochemical technique often used for subsecond detection of small molecule neurotransmitters, in vivo. A few peptides have been detected with FSCV; however, a detailed analysis of the electrochemical signature of all electroactive amino acids with FSCV has not been fully investigated. Because the mechanisms, locations, and timescales for signaling peptide release in the brain are relatively unexplored, developing sensitive and selective tools capable of quantitating neuropeptide signaling is essential. To bridge this gap, we used FSCV to characterize the electroactive amino acids: cysteine, methionine, histidine, tryptophan, and tyrosine. We show that tyrosine, tryptophan, and histidine are easily oxidized on carbon fiber surfaces with FSCV, while detection of the sulfur-containing amino acids is more difficult. This study provides critical information for electrochemical waveform design and optimization for detection of peptides containing these amino acids.

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28

Ramírez, Pablo, Héctor Toledo, Nicolas Guiliani, and Carlos A. Jerez. "An Exported Rhodanese-Like Protein Is Induced during Growth of Acidithiobacillus ferrooxidans in Metal Sulfides and Different Sulfur Compounds." Applied and Environmental Microbiology 68, no. 4 (April 2002): 1837–45. http://dx.doi.org/10.1128/aem.68.4.1837-1845.2002.

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ABSTRACT By proteomic analysis we found a 21-kDa protein (P21) from Acidithiobacillus ferrooxidans ATCC 19859 whose synthesis was greatly increased by growth of the bacteria in pyrite, thiosulfate, elemental sulfur, CuS, and ZnS and was almost completely repressed by growth in ferrous iron. After we determined the N-terminal amino acid sequence of P21, we used the available preliminary genomic sequence of A. ferrooxidans ATCC 23270 to isolate the DNA region containing the p21 gene. The nucleotide sequence of this DNA fragment contained a putative open reading frame (ORF) coding for a 23-kDa protein. This difference in size was due to the presence of a putative signal peptide in the ORF coding for P21. When p21 was cloned and overexpressed in Escherichia coli, the signal peptide was removed, resulting in a mature protein with a molecular mass of 21 kDa and a calculated isoelectric point of 9.18. P21 exhibited 27% identity and 42% similarity to the Deinococcus radiodurans thiosulfate-sulfur transferase (rhodanese; EC 2.8.1.1) and similar values in relation to other rhodaneses, conserving structural domains and an active site with a cysteine, both characteristic of this family of proteins. However, the purified recombinant P21 protein did not show rhodanese activity. Unlike cytoplasmic rhodaneses, P21 was located in the periphery of A. ferrooxidans cells, as determined by immunocytochemical analysis, and was regulated depending on the oxidizable substrate. The genomic context around gene p21 contained other ORFs corresponding to proteins such as thioredoxins and sulfate-thiosulfate binding proteins, clearly suggesting the involvement of P21 in inorganic sulfur metabolism in A. ferrooxidans.

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29

Sanden, Sebastian A., Ruiqin Yi, Masahiko Hara, and Shawn E. McGlynn. "Simultaneous synthesis of thioesters and iron–sulfur clusters in water: two universal components of energy metabolism." Chemical Communications 56, no. 80 (2020): 11989–92. http://dx.doi.org/10.1039/d0cc04078a.

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30

Shono, Shigeaki, Nobuko Mataga, and Kiyoshi Toda. "The Two Dimensional Peptide Mappings of the Nail Low Sulfur S-carboxymethyl Keratins." Journal of Dermatology 14, no. 5 (October 1987): 419–26. http://dx.doi.org/10.1111/j.1346-8138.1987.tb03603.x.

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31

Bobrowski, Krzysztof, Gordon L. Hug, Dariusz Pogocki, Bronislaw Marciniak, and Christian Schöneich. "Sulfur Radical Cation−Peptide Bond Complex in the One-Electron Oxidation ofS-Methylglutathione." Journal of the American Chemical Society 129, no. 29 (July 2007): 9236–45. http://dx.doi.org/10.1021/ja072301f.

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32

Dunbar, Kyle L., Maria Dell, Finn Gude, and Christian Hertweck. "Reconstitution of polythioamide antibiotic backbone formation reveals unusual thiotemplated assembly strategy." Proceedings of the National Academy of Sciences 117, no. 16 (April 7, 2020): 8850–58. http://dx.doi.org/10.1073/pnas.1918759117.

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Closthioamide (CTA) is a rare example of a thioamide-containing nonribosomal peptide and is one of only a handful of secondary metabolites described from obligately anaerobic bacteria. Although the biosynthetic gene cluster responsible for CTA production and the thioamide synthetase that catalyzes sulfur incorporation were recently discovered, the logic for peptide backbone assembly has remained a mystery. Here, through the use of in vitro biochemical assays, we demonstrate that the amide backbone of CTA is assembled in an unusual thiotemplated pathway involving the cooperation of a transacylating member of the papain-like cysteine protease family and an iteratively acting ATP-grasp protein. Using the ATP-grasp protein as a bioinformatic handle, we identified hundreds of such thiotemplated yet nonribosomal peptide synthetase (NRPS)-independent biosynthetic gene clusters across diverse bacterial phyla. The data presented herein not only clarify the pathway for the biosynthesis of CTA, but also provide a foundation for the discovery of additional secondary metabolites produced by noncanonical biosynthetic pathways.

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33

Wagner-Huber, R., U. Fischer, R. Brunisholz, M. Rümbeli, G. Frank, and H. Zuber. "The Primary Structure of the Presumable BChl d-Binding Polypeptide of Chlorobium vibrioforme f. thiosulfatophilum." Zeitschrift für Naturforschung C 45, no. 7-8 (August 1, 1990): 818–22. http://dx.doi.org/10.1515/znc-1990-7-812.

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Abstract In addition to the previous isolated and sequenced polypeptides from green photosynthetic sulfur bacteria, which are presumably involved in binding BChl c and e, an analogous poly- peptide has been purified from the BChl d-containing bacterium Chlorobium vibrioforme f. thiosulfatophilum. The primary structure of this 6.15 kDa polypeptide was determined. It shows an extremely high homology (98.3%) to the corresponding polypeptide from Pelodictyon luteolum, indicative of an important functional role.

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34

Brügger, Kim, Lanming Chen, Markus Stark, Arne Zibat, Peter Redder, Andreas Ruepp, Mariana Awayez, Qunxin She, Roger A. Garrett, and Hans-Peter Klenk. "The genome ofHyperthermus butylicus: a sulfur-reducing, peptide fermenting, neutrophilic Crenarchaeote growing up to 108 °C." Archaea 2, no. 2 (2007): 127–35. http://dx.doi.org/10.1155/2007/745987.

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Hyperthermus butylicus, a hyperthermophilic neutrophile and anaerobe, is a member of the archaeal kingdom Crenarchaeota. Its genome consists of a single circular chromosome of 1,667,163 bp with a 53.7% G+C content. A total of 1672 genes were annotated, of which 1602 are protein-coding, and up to a third are specific toH. butylicus. In contrast to some other crenarchaeal genomes, a high level of GUG and UUG start codons are predicted. Twocdc6genes are present, but neither could be linked unambiguously to an origin of replication. Many of the predicted metabolic gene products are associated with the fermentation of peptide mixtures including several peptidases with diverse specificities, and there are many encoded transporters. Most of the sulfur-reducing enzymes, hydrogenases and electron-transfer proteins were identified which are associated with energy production by reducing sulfur to H2S. Two large clusters of regularly interspaced repeats (CRISPRs) are present, one of which is associated with a crenarchaeal-typecasgene superoperon; none of the spacer sequences yielded good sequence matches with known archaeal chromosomal elements. The genome carries no detectable transposable or integrated elements, no inteins, and introns are exclusive to tRNA genes. This suggests that the genome structure is quite stable, possibly reflecting a constant, and relatively uncompetitive, natural environment.

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35

RIDGE, RICHARD J., GARY R. MATSUEDA, EDGAR HABER, and REI MATSUEDA. "Sulfur protection with the 3-nitro-2-pyridinesulfenyl group in solid-phase peptide synthesis." International Journal of Peptide and Protein Research 19, no. 5 (January 12, 2009): 490–98. http://dx.doi.org/10.1111/j.1399-3011.1982.tb02634.x.

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36

Galardon, Erwan, Michel Giorgi, and Isabelle Artaud. "Modeling the inhibition of peptide deformylase by hydroxamic acids: influence of the sulfur donor." Dalton Transactions, no. 10 (2007): 1047. http://dx.doi.org/10.1039/b616212f.

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37

Perell, Gabriella T., Rachel Lynn Staebell, Mehrdad Hairani, Alessandro Cembran, and William C. K. Pomerantz. "Tuning Sulfur Oxidation States on Thioether-Bridged Peptide Macrocycles for Modulation of Protein Interactions." ChemBioChem 18, no. 18 (August 7, 2017): 1836–44. http://dx.doi.org/10.1002/cbic.201700222.

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38

Michel, Andre G., Chakib Ameziane-Hassani, Gaston Boulay, and Gilles Lajoie. "Étude structurale de la liaison thioamide: Synthèse et conformation de dérivés de la thioalanine et de la thioglycine." Canadian Journal of Chemistry 67, no. 8 (August 1, 1989): 1312–18. http://dx.doi.org/10.1139/v89-202.

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The present study reports the synthesis, crystal structure determinations, and the conformational analysis of N-tertiobutyloxycarbonyl N′-methylthioalanine (Boc-AlaS-NHCH3, C9H18N2O2S) and of N-tertiobutyloxycarbonyl N′-methylthioglycine (Boc-GlyS-NHCH3, C8H16N2O2S). The particular feature of these compounds is the replacement of the classical oxopeptide linkage by a thioamide bond. Crystals of Boc-AlaS-NHCH3 are tetragonal, space group P43212. Those of Boc-GlyS-NHCH3 are monoclinic, space group P21/c. Both structures were solved by direct methods and refined by full-matrix least-squares methods to Rw = 0.045 and 0.035 for 827 and 1335 reflections respectively, with intensities greater than 2.5σ(I). The conformations of both compounds correspond to conformational energy minima, calculated for classical amino acids. The C=S bond lengths of 1.665(9) and 1.650(3) Å constitute the major difference compared to oxopeptides; the crystal structures reveal that the presence of the sulfur atom does not change the electronic properties of the peptide bond. Using a classical method for the study of peptides (ECEPP/2), conformational energy maps were computed for derivatives of dithioalanine and dithioglycine and are compared to the oxo residues. We conclude that the synthesis and conformational analysis of thionated amino acids allow us to introduce the thioamide linkage into more complex peptide structures and to predict the conformational behaviour. Keywords: molecular conformations, peptidic structure, crystallography.

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39

Balty, Clémence, Alain Guillot, Laura Fradale, Clémence Brewee, Benjamin Lefranc, Christian Herrero, Corine Sandström, Jérôme Leprince, Olivier Berteau, and Alhosna Benjdia. "Biosynthesis of the sactipeptide Ruminococcin C by the human microbiome: Mechanistic insights into thioether bond formation by radical SAM enzymes." Journal of Biological Chemistry 295, no. 49 (September 24, 2020): 16665–77. http://dx.doi.org/10.1074/jbc.ra120.015371.

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Despite its major importance in human health, the metabolic potential of the human gut microbiota is still poorly understood. We have recently shown that biosynthesis of Ruminococcin C (RumC), a novel ribosomally synthesized and posttranslationally modified peptide (RiPP) produced by the commensal bacterium Ruminococcus gnavus, requires two radical SAM enzymes (RumMC1 and RumMC2) catalyzing the formation of four Cα-thioether bridges. These bridges, which are essential for RumC's antibiotic properties against human pathogens such as Clostridium perfringens, define two hairpin domains giving this sactipeptide (sulfur-to-α-carbon thioether–containing peptide) an unusual architecture among natural products. We report here the biochemical and spectroscopic characterizations of RumMC2. EPR spectroscopy and mutagenesis data support that RumMC2 is a member of the large family of SPASM domain radical SAM enzymes characterized by the presence of three [4Fe-4S] clusters. We also demonstrate that this enzyme initiates its reaction by Cα H-atom abstraction and is able to catalyze the formation of nonnatural thioether bonds in engineered peptide substrates. Unexpectedly, our data support the formation of a ketoimine rather than an α,β-dehydro-amino acid intermediate during Cα-thioether bridge LC–MS/MS fragmentation. Finally, we explored the roles of the leader peptide and of the RiPP precursor peptide recognition element, present in myriad RiPP-modifying enzymes. Collectively, our data support a more complex role for the peptide recognition element and the core peptide for the installation of posttranslational modifications in RiPPs than previously anticipated and suggest a possible reaction intermediate for thioether bond formation.

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40

Mukhopadhyaya, Pratap N., Chirajyoti Deb, Chandrajit Lahiri, and Pradosh Roy. "A soxA Gene, Encoding a Diheme Cytochrome c, and a sox Locus, Essential for Sulfur Oxidation in a New Sulfur Lithotrophic Bacterium." Journal of Bacteriology 182, no. 15 (August 1, 2000): 4278–87. http://dx.doi.org/10.1128/jb.182.15.4278-4287.2000.

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ABSTRACT A mobilizable suicide vector, pSUP5011, was used to introduce Tn5-mob in a new facultative sulfur lithotrophic bacterium, KCT001, to generate mutants defective in sulfur oxidation (Sox−). The Sox− mutants were unable to oxidize thiosulfate while grown mixotrophically in the presence of thiosulfate and succinate. The mutants were also impaired in oxidizing other reduced sulfur compounds and elemental sulfur as evident from the study of substrate oxidation by the whole cells. Sulfite oxidase activity was significantly diminished in the cell extracts of all the mutants. A soxA gene was identified from the transposon-adjacent genomic DNA of a Sox− mutant strain. The sequence analysis revealed that the soxA open reading frame (ORF) is preceded by a potential ribosome binding site and promoter region with −10- and −35-like sequences. The deduced nucleotide sequence of the soxA gene was predicted to code for a protein of 286 amino acids. It had a signal peptide of 26 N-terminal amino acids. The amino acid sequence showed similarity with a putative gene product of Aquifex aeolicus, soluble cytochrome c 551 of Chlorobium limicola, and the available partial SoxA sequence ofParacoccus denitrificans. The soxA-encoded product seems to be a diheme cytochrome c for KCT001 andA. aeolicus, but the amino acid sequence of C. limicola cytochrome c 551 revealed a single heme-binding region. Another transposon insertion mutation was mapped within the soxA ORF. Four other independent transposon insertion mutations were mapped in the 4.4-kbsoxA contiguous genomic DNA region. The results thus suggest that a sox locus of KCT001, essential for sulfur oxidation, was affected by all these six independent insertion mutations.

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41

Coolong, Timothy W., and William M. Randle. "Sulfur and Nitrogen Availability Interact to Affect the Flavor Biosynthetic Pathway in Onion." Journal of the American Society for Horticultural Science 128, no. 5 (September 2003): 776–83. http://dx.doi.org/10.21273/jashs.128.5.0776.

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To determine the extent to which sulfur (S) and nitrogen (N) fertility interact to influence the flavor biosynthetic pathway in onion (Allium cepa L.), `Granex 33' onions were grown in hydroponic solution culture with varying levels of S and N availability. Plants were grown at 5, 45, or 125 mg·L-1 sulfate (SO42-), and 10, 50, 90, or 130 mg·L-1 N, in a factorial combination. Total bulb S, total and individual flavor precursors and their peptide intermediates in intact onion tissue were measured. To measure the effect of S and N on alliinase activity, flavor precursors were also measured in onion macerates. Sulfur and N availability in the hydroponics solution interacted to influence all flavor compounds except S-methyl-L-cysteine sulfoxide. Levels of S-methyl-L-cysteine sulfoxide were influenced by N and S levels in the solutions; however, no interaction was present. At the lowest SO 42- or N levels, most precursors and peptides measured were present in very low concentrations. When SO 42- or N availability was adequate, differences among flavor compounds were small. Results indicated that S fertility had a greater influence on trans-S-1-propenyl-L-cysteine sulfoxide (1-PRENCSO) accumulation, while N availability had a greater influence on S-methyl-L-cysteine sulfoxide levels. Flavor precursors remaining in the onion macerates revealed that the percentage of intact precursors hydrolyzed by alliinase were not significantly influenced by either SO 42- or N levels in the solutions, except for 1-PRENCSO, which was affected by N levels. Nitrogen and S fertility interacted to influence the flavor biosynthetic pathway and may need to be considered together when manipulating onion flavor compounds.

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42

Friedrich, Cornelius G., Armin Quentmeier, Frank Bardischewsky, Dagmar Rother, Regine Kraft, Susanne Kostka, and Heino Prinz. "Novel Genes Coding for Lithotrophic Sulfur Oxidation of Paracoccus pantotrophus GB17." Journal of Bacteriology 182, no. 17 (September 1, 2000): 4677–87. http://dx.doi.org/10.1128/jb.182.17.4677-4687.2000.

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ABSTRACT The gene region coding for lithotrophic sulfur oxidation ofParacoccus pantotrophus GB17 is located on a 13-kb insert of plasmid pEG12. Upstream of the previously described six open reading frames (ORFs) soxABCDEF with a partial sequence ofsoxA and soxF (C. Wodara, F. Bardischewsky, and C. G. Friedrich, J. Bacteriol. 179:5014–5023, 1997), 4,350 bp were sequenced. The sequence completed soxA, and uncovered six new ORFs upstream of soxA, designated ORF1, ORF2, and ORF3, and soxXYZ. ORF1 could encode a 275-amino-acid polypeptide of 29,332 Da with a 61 to 63% similarity to LysR transcriptional regulators. ORF2 could encode a 245-amino-acid polypeptide of 26,022 Da with the potential to form six transmembrane helices and with a 48 to 51% similarity to proteins involved in redox transport in cytochrome c biogenesis. ORF3 could encode a periplasmic polypeptide of 186 amino acids of 20,638 Da with a similarity to thioredoxin-like proteins and with a putative signal peptide of 21 amino acids. Purified SoxXA, SoxYZ, and SoxB are essential for thiosulfate or sulfite-dependent cytochrome creduction in vitro. N-terminal and internal amino acid sequences identified SoxX, SoxY, SoxZ, and SoxA to be coded by the respective genes. The molecular masses of the mature proteins determined by electrospray ionization spectroscopy (SoxX, 14,834 Da; SoxY, 11,094 Da; SoxZ, 11,717 Da; and SoxA, 30,452 Da) were identical or close to those deduced from the nucleotide sequence with differences for the covalent heme moieties. SoxXA represents a novel type of periplasmicc-type cytochromes, with SoxX as a monoheme and SoxA as a hybrid diheme cytochrome c. SoxYZ is an as-yet-unprecedented soluble protein. SoxY has a putative signal peptide with a twin arginine motif and possibly cotransports SoxZ to the periplasm. SoxYZ neither contains a metal nor a complex redox center, as proposed for proteins likely to be transported via the Tat system.

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43

Milner-White, E. James. "Protein three-dimensional structures at the origin of life." Interface Focus 9, no. 6 (October 18, 2019): 20190057. http://dx.doi.org/10.1098/rsfs.2019.0057.

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Proteins are relatively easy to synthesize, compared to nucleic acids and it is likely that there existed a stage prior to the RNA world which can be called the protein world. Some of the three-dimensional (3D) peptide structures in these proteins have, we argue, been conserved since then and may constitute the oldest biological relics in existence. We focus on 3D peptide motifs consisting of up to eight or so amino acid residues. The best known of these is the ‘nest’, a three- to seven-residue protein motif, which has the function of binding anionic atoms or groups of atoms. Ten per cent of amino acids in typical proteins belong to a nest, so it is a common motif. A five-residue nest is found as part of the well-known P-loop that is a recurring feature of many ATP or GTP-binding proteins and it has the function of binding the phosphate part of these ligands. A synthetic hexapeptide, ser–gly–ala–gly–lys–thr, designed to resemble the P-loop, has been shown to bind inorganic phosphate. Another type of nest binds iron–sulfur centres. A range of other simple motifs occur with various intriguing 3D structures; others bind cations or form channels that transport potassium ions; other peptides form catalytically active haem-like or sheet structures with certain transition metals. Amyloid peptides are also discussed. It now seems that the earliest polypeptides were far from being functionless stretches, and had many of the properties, both binding and catalytic, that might be expected to encourage and stabilize simple life forms in the hydrothermal vents of ocean depths.

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44

Bonfio, Claudia, Elisa Godino, Maddalena Corsini, Fabrizia Fabrizi de Biani, Graziano Guella, and Sheref S. Mansy. "Prebiotic iron–sulfur peptide catalysts generate a pH gradient across model membranes of late protocells." Nature Catalysis 1, no. 8 (July 30, 2018): 616–23. http://dx.doi.org/10.1038/s41929-018-0116-3.

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45

Baecker, Daniel, and Sebastian Guenther. "General Applicability of High-Resolution Continuum-Source Graphite Furnace Molecular Absorption Spectrometry to the Quantification of Oligopeptides Using the Example of Glutathione." Analytica 3, no. 1 (January 16, 2022): 24–35. http://dx.doi.org/10.3390/analytica3010003.

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This communication introduces the first-time application of high-resolution continuum-source molecular absorption spectrometry (HR CS MAS) for the quantification of a peptide. The graphite furnace technique was employed and the tripeptide glutathione (GSH) served as a model compound. Based on measuring sulfur in terms of carbon monosulfide (CS), a method was elaborated to analyze aqueous solutions of GSH. The most prominent wavelength of the CS molecule occurred at 258.0560 nm and was adduced for monitoring. The methodological development covered the optimization of the pyrolysis and vaporization temperatures. These were found optimally to be 250 °C and 2250 °C, respectively. Moreover, the effect of modifiers (zirconium, calcium, magnesium, palladium) on the absorption signals was investigated. The best results were obtained after permanent coating of the graphite tube with zirconium (total amount of 400 μg) and adding a combination of palladium (10 µL, 10 g L−1) and calcium (2 µL, 1 g L−1) as a chemical modifier to the probes (10 µL). Aqueous standard samples of GSH were used for the calibration. It showed a linear range of 2.5–100 µg mL−1 sulfur contained in GSH with a correlation coefficient R2 > 0.997. The developed method exhibited a limit of detection (LOD) and quantification (LOQ) of 2.1 µg mL−1 and 4.3 µg mL−1 sulfur, respectively. The characteristic mass accounted for 5.9 ng sulfur. The method confirmed the general suitability of MAS for the analysis of an oligopeptide. Thus, this study serves as groundwork for further development in order to extend the application of classical atomic absorption spectrometry (AAS).

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46

Randle, William M., Jane E. Lancaster, Martin L. Shaw, Kevin H. Sutton, Rob L. Hay, and Mark L. Bussard. "Quantifying Onion Flavor Compounds Responding to Sulfur Fertility-Sulfur Increases Levels of Alk(en)yl Cysteine Sulfoxides and Biosynthetic Intermediates." Journal of the American Society for Horticultural Science 120, no. 6 (November 1995): 1075–81. http://dx.doi.org/10.21273/jashs.120.6.1075.

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Three onion (Allium cepa L.) cultivars were grown to maturity at five S fertility levels and analyzed for S-alk(en)yl-L-cysteine sulfoxide (ACSO) flavor precursors, γ-glutamyl peptide (γ-GP) intermediates, bulb S, pyruvic acid, and soluble solids content. ACSO concentration and composition changed with S fertility, and the response was cultivar dependent. At S treatments that induced S deficiency symptoms during active bulbing, (+)S-methyl-L-cysteine sulfoxide was the dominant flavor precursor, and the flavor pathway was a strong sink for available S. As S fertility increased to luxuriant levels, trans(+)-S-(1-propenyl)-L-cysteine sulfoxide (PRENCSO) became the dominant ACSO. (+)S-propyl-L-cysteine sulfoxide was found in low concentration relative to total ACSO at all S fertility treatments. With low S fertility, S rapidly was metabolized and low γ-GP concentrations were detected. As S fertility increased, γ-GP increased, especially γ-L-glutamyl-S-(1-propenyl)-L-cysteine sulfoxide, the penultimate compound leading to ACSO synthesis. Nearly 95% of the total bulb S could be accounted for in the measured S compounds at low S fertility. However, at the highest S treatment, only 40 % of the total bulb S could be attributed to the ACSO and γ-GP, indicating that other S compounds were significant S reservoirs in onions. Concentrations of enzymatically produced pyruvic acid (EPY) were most closely related to PRENCSO concentrations. Understanding the dynamics of flavor accumulation in onion and other vegetable Alliums will become increasing important as the food and phytomedicinal industries move toward greater product standardization and characterization.

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Schwob, Lucas, Simon Dörner, Kaan Atak, Kaja Schubert, Martin Timm, Christine Bülow, Vicente Zamudio-Bayer, et al. "Site-Selective Dissociation upon Sulfur L-Edge X-ray Absorption in a Gas-Phase Protonated Peptide." Journal of Physical Chemistry Letters 11, no. 4 (January 24, 2020): 1215–21. http://dx.doi.org/10.1021/acs.jpclett.0c00041.

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Wu, Size, and Xiyuan Lin. "Trials in developing a nanoscale material for extravascular contrast-enhanced ultrasound targeting hepatocellular carcinoma." PeerJ 8 (December 7, 2020): e10403. http://dx.doi.org/10.7717/peerj.10403.

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Background Medical imaging is an important approach for the diagnosis of hepatocellular carcinoma (HCC), a common life threaten disease, however, the diagnostic efficiency is still not optimal. Developing a novel method to improve diagnosis is necessary. The aim of this project was to formulate a material that can combine with GPC3 of HCC for targeted enhanced ultrasound. Methods A material of sulfur hexafluoride (SF6) filled liposome microbubbles and conjugated with synthesized peptide (LSPMbs) was prepared and assessed in vitro and vivo. Liposome microbubbles were made of DPPC, DPPG, DSPE-PEG2000,and SF6, using thin film method to form shell, followed filling SF6, and conjugating peptide. A carbodiimide method was used for covalent conjugation of peptide to LSMbs. Results The prepared LSPMbs appeared round shaped, with size of 380.9 ± 176.5 nm, and Zeta potential of −51.4 ± 10.4mV. LSPMbs showed high affinity to Huh-7 cells in vitro, presented good enhanced ultrasound effects, did not show cytotoxicity, and did not exhibit targeted fluorescence and enhanced ultrasound in animal xenograft tumors. Conclusion Extravascular contrast-enhanced ultrasound targeted GPC3 on HCC may not be realized, and the reason may be that targeted contrast agents of microbubbles are hard to access and accumulate in the tumor stroma and matrix.

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Ma, Ming, Jeremy R. Lohman, Tao Liu, and Ben Shen. "C-S bond cleavage by a polyketide synthase domain." Proceedings of the National Academy of Sciences 112, no. 33 (August 3, 2015): 10359–64. http://dx.doi.org/10.1073/pnas.1508437112.

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Leinamycin (LNM) is a sulfur-containing antitumor antibiotic featuring an unusual 1,3-dioxo-1,2-dithiolane moiety that is spiro-fused to a thiazole-containing 18-membered lactam ring. The 1,3-dioxo-1,2-dithiolane moiety is essential for LNM’s antitumor activity, by virtue of its ability to generate an episulfonium ion intermediate capable of alkylating DNA. We have previously cloned and sequenced the lnm gene cluster from Streptomyces atroolivaceus S-140. In vivo and in vitro characterizations of the LNM biosynthetic machinery have since established that: (i) the 18-membered macrolactam backbone is synthesized by LnmP, LnmQ, LnmJ, LnmI, and LnmG, (ii) the alkyl branch at C-3 of LNM is installed by LnmK, LnmL, LnmM, and LnmF, and (iii) leinamycin E1 (LNM E1), bearing a thiol moiety at C-3, is the nascent product of the LNM hybrid nonribosomal peptide synthetase (NRPS)-acyltransferase (AT)-less type I polyketide synthase (PKS). Sulfur incorporation at C-3 of LNM E1, however, has not been addressed. Here we report that: (i) the bioinformatics analysis reveals a pyridoxal phosphate (PLP)-dependent domain, we termed cysteine lyase (SH) domain (LnmJ-SH), within PKS module-8 of LnmJ; (ii) the LnmJ-SH domain catalyzes C-S bond cleavage by using l-cysteine and l-cysteine S-modified analogs as substrates through a PLP-dependent β-elimination reaction, establishing l-cysteine as the origin of sulfur at C-3 of LNM; and (iii) the LnmJ-SH domain, sharing no sequence homology with any other enzymes catalyzing C-S bond cleavage, represents a new family of PKS domains that expands the chemistry and enzymology of PKSs and might be exploited to incorporate sulfur into polyketide natural products by PKS engineering.

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Krezel, A., and W. Bal. "Coordination chemistry of glutathione." Acta Biochimica Polonica 46, no. 3 (September 30, 1999): 567–80. http://dx.doi.org/10.18388/abp.1999_4129.

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The metal ion coordination abilities of reduced and oxidized glutathione are reviewed. Reduced glutathione (GSH) is a very versatile ligand, forming stable complexes with both hard and soft metal ions. Several general binding modes of GSH are described. Soft metal ions coordinate exclusively or primarily through thiol sulfur. Hard ones prefer the amino acid-like moiety of the glutamic acid residue. Several transition metal ions can additionally coordinate to the peptide nitrogen of the gamma-Glu-Cys bond. Oxidized glutathione lacks the thiol function. Nevertheless, it proves to be a surprisingly efficient ligand for a range of metal ions, coordinating them primarily through the donors of the glutamic acid residue.

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