Academic literature on the topic 'C-terminal loop'
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Journal articles on the topic "C-terminal loop"
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MONLEÓN, Daniel, Vicent ESTEVE, Helena KOVACS, Juan J. CALVETE, and Bernardo CELDA. "Conformation and concerted dynamics of the integrin-binding site and the C-terminal region of echistatin revealed by homonuclear NMR." Biochemical Journal 387, no. 1 (March 22, 2005): 57–66. http://dx.doi.org/10.1042/bj20041343.
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Echistatin is a potent antagonist of the integrins αvβ3, α5β1 and αIIbβ3. Its full inhibitory activity depends on an RGD (Arg-Gly-Asp) motif expressed at the tip of the integrin-binding loop and on its C-terminal tail. Previous NMR structures of echistatin showed a poorly defined integrin-recognition sequence and an incomplete C-terminal tail, which left the molecular basis of the functional synergy between the RGD loop and the C-terminal region unresolved. We report a high-resolution structure of echistatin and an analysis of its internal motions by off-resonance ROESY (rotating-frame Overhauser enhancement spectroscopy). The full-length C-terminal polypeptide is visible as a β-hairpin running parallel to the RGD loop and exposing at the tip residues Pro43, His44 and Lys45. The side chains of the amino acids of the RGD motif have well-defined conformations. The integrin-binding loop displays an overall movement with maximal amplitude of 30°. Internal angular motions in the 100–300 ps timescale indicate increased flexibility for the backbone atoms at the base of the integrin-recognition loop. In addition, backbone atoms of the amino acids Ala23 (flanking the R24GD26 tripeptide) and Asp26 of the integrin-binding motif showed increased angular mobility, suggesting the existence of major and minor hinge effects at the base and the tip, respectively, of the RGD loop. A strong network of NOEs (nuclear Overhauser effects) between residues of the RGD loop and the C-terminal tail indicate concerted motions between these two functional regions. A full-length echistatin–αvβ3 docking model suggests that echistatin's C-terminal amino acids may contact αv-subunit residues and provides new insights to delineate structure–function correlations.
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Harouaka, Djamila, and Gail W. Wertz. "Mutations in the C-Terminal Loop of the Nucleocapsid Protein Affect Vesicular Stomatitis Virus RNA Replication and Transcription Differentially." Journal of Virology 83, no. 22 (September 2, 2009): 11429–39. http://dx.doi.org/10.1128/jvi.00813-09.
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ABSTRACT The 2.9-Å structure of the vesicular stomatitis virus nucleocapsid (N) protein bound to RNA shows the RNA to be tightly sequestered between the two lobes of the N protein. Domain movement of the lobes of the N protein has been postulated to facilitate polymerase access to the RNA template. We investigated the roles of individual amino acid residues in the C-terminal loop, involved in long-range interactions between N protein monomers, in forming functional ribonucleoprotein (RNP) templates. The effects of specific N protein mutations on its expression, interaction with the phosphoprotein, and formation of RNP templates that supported viral RNA replication and transcription were examined. Mutations introduced into the C-terminal loop, predicted to break contact with other residues in the loop, caused up to 10-fold increases in RNA replication without an equivalent stimulation of transcription. Mutation F348A, predicted to break contact between the C-terminal loop and the N-terminal arm, formed templates that supported wild-type levels of RNA replication but almost no transcription. These data show that mutations in the C-terminal loop of the N protein can disparately affect RNA replication and transcription, indicating that the N protein plays a role in modulating RNP template function beyond its structural role in RNA encapsidation.
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Burkhart, Michael D., Paul D'Agostino, Samuel C. Kayman, and Abraham Pinter. "Involvement of the C-Terminal Disulfide-Bonded Loop of Murine Leukemia Virus SU Protein in a Postbinding Step Critical for Viral Entry." Journal of Virology 79, no. 12 (June 15, 2005): 7868–76. http://dx.doi.org/10.1128/jvi.79.12.7868-7876.2005.
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ABSTRACT A role for the C-terminal domain (CTD) of murine leukemia virus (MuLV) Env protein in viral fusion was indicated by the potent inhibition of MuLV-induced fusion, but not receptor binding, by two rat monoclonal antibodies (MAbs) specific for epitopes in the CTD. Although these two MAbs, 35/56 and 83A25, have very different patterns of reactivity with viral isolates, determinants of both epitopes were mapped to the last C-terminal disulfide-bonded loop of SU (loop 10), and residues in this loop responsible for the different specificities of these MAbs were identified. Both MAbs reacted with a minor fraction of a truncated SU fragment terminating four residues after loop 10, indicating that while the deleted C-terminal residues were not part of these epitopes, they promoted their formation. Neither MAb recognized the loop 10 region expressed in isolated form, suggesting that these epitopes were not completely localized within loop 10 but required additional sequences located N terminal to the loop. Direct support for a role for loop 10 in fusion was provided by the demonstration that Env mutants containing an extra serine or threonine residue between the second and third positions of the loop were highly attenuated for infectivity and defective in fusion assays, despite wild-type levels of expression, processing, and receptor binding. Other mutations at positions 1 to 3 of loop 10 inhibited processing of the gPr80 precursor protein or led to increased shedding of SU, suggesting that loop 10 also affects Env folding and the stability of the interaction between SU and TM.
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Qiao, Renping, Florian Weissmann, Masaya Yamaguchi, Nicholas G. Brown, Ryan VanderLinden, Richard Imre, Marc A. Jarvis, et al. "Mechanism of APC/CCDC20 activation by mitotic phosphorylation." Proceedings of the National Academy of Sciences 113, no. 19 (April 25, 2016): E2570—E2578. http://dx.doi.org/10.1073/pnas.1604929113.
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Chromosome segregation and mitotic exit are initiated by the 1.2-MDa ubiquitin ligase APC/C (anaphase-promoting complex/cyclosome) and its coactivator CDC20 (cell division cycle 20). To avoid chromosome missegregation, APC/CCDC20 activation is tightly controlled. CDC20 only associates with APC/C in mitosis when APC/C has become phosphorylated and is further inhibited by a mitotic checkpoint complex until all chromosomes are bioriented on the spindle. APC/C contains 14 different types of subunits, most of which are phosphorylated in mitosis on multiple sites. However, it is unknown which of these phospho-sites enable APC/CCDC20 activation and by which mechanism. Here we have identified 68 evolutionarily conserved mitotic phospho-sites on human APC/C bound to CDC20 and have used the biGBac technique to generate 47 APC/C mutants in which either all 68 sites or subsets of them were replaced by nonphosphorylatable or phospho-mimicking residues. The characterization of these complexes in substrate ubiquitination and degradation assays indicates that phosphorylation of an N-terminal loop region in APC1 is sufficient for binding and activation of APC/C by CDC20. Deletion of the N-terminal APC1 loop enables APC/CCDC20 activation in the absence of mitotic phosphorylation or phospho-mimicking mutations. These results indicate that binding of CDC20 to APC/C is normally prevented by an autoinhibitory loop in APC1 and that its mitotic phosphorylation relieves this inhibition. The predicted location of the N-terminal APC1 loop implies that this loop controls interactions between the N-terminal domain of CDC20 and APC1 and APC8. These results reveal how APC/C phosphorylation enables CDC20 to bind and activate the APC/C in mitosis.
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Takemoto, D. J., L. J. Takemoto, J. Hansen, and D. Morrison. "Regulation of retinal transducin by C-terminal peptides of rhodopsin." Biochemical Journal 232, no. 3 (December 15, 1985): 669–72. http://dx.doi.org/10.1042/bj2320669.
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Transducin is a multi-subunit guanine-nucleotide-binding protein that mediates signal coupling between rhodopsin and cyclic GMP phosphodiesterase in retinal rod outer segments. Whereas the T alpha subunit of transducin binds guanine nucleotides and is the activator of the phosphodiesterase, the T beta gamma subunit may function to link physically T alpha with photolysed rhodopsin. In order to determine the binding sites of rhodopsin to transducin, we have synthesized eight peptides (Rhod-1 etc.) that correspond to the C-terminal regions of rhodopsin and to several external and one internal loop region. These peptides were tested for their inhibition of restored GTPase activity of purified transducin reconstituted into depleted rod-outer-segment disc membranes. A marked inhibition of GTPase activity was observed when transducin was pre-incubated with peptides Rhod-1, Rhod-2 and Rhod-3. These peptides correspond to opsin amino acid residues 332-339, 324-331 and 317-321 respectively. Peptides corresponding to the three external loop regions or to the C-terminal residues 341-348 did not inhibit reconsituted GTPase activity. Likewise, Rhod-8, a peptide corresponding to an internal loop region of rhodopsin, did not inhibit GTPase activity. These findings support the concept that these specific regions of the C-terminus of rhodopsin serve as recognition sites for transducin.
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Ren, Chunguang, Satoshi Nagao, Masaru Yamanaka, Hirofumi Komori, Yasuhito Shomura, Yoshiki Higuchi, and Shun Hirota. "Oligomerization enhancement and two domain swapping mode detection for thermostable cytochrome c552via the elongation of the major hinge loop." Molecular BioSystems 11, no. 12 (2015): 3218–21. http://dx.doi.org/10.1039/c5mb00545k.
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High-order oligomers increased whereas N-terminal domain swapping and C-terminal domain swapping were elucidated by the insertion of Gly residues at the major hinge loop of cytochrome c552.
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Bury, Loredana, Emanuela Falcinelli, Haripriya Kuchi Bhotla, Anna Maria Mezzasoma, Giuseppe Guglielmini, Alexander Tischer, Laurie Moon-Tasson, Matthew Auton, and Paolo Gresele. "A p.Arg127Gln variant in GPIbα LRR5 allosterically enhances affinity for VWF: a novel form of platelet-type VWD." Blood Advances 6, no. 7 (April 1, 2022): 2236–46. http://dx.doi.org/10.1182/bloodadvances.2021005463.
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Abstract Gain-of-function (GOF) variants in GP1BA cause platelet-type von Willebrand disease (PT-VWD), a rare inherited autosomal dominant bleeding disorder characterized by enhanced platelet GPIbα to von Willebrand factor (VWF) interaction, and thrombocytopenia. To date, only 6 variants causing PT-VWD have been described, 5 in the C-terminal disulfide loop of the VWF-binding domain of GPIbα and 1 in the macroglycopeptide. GOF GP1BA variants generate a high-affinity conformation of the C-terminal disulfide loop with a consequent allosteric conformational change on another region of GPIbα, the leucine-rich-repeat (LRR) domain. We identified a novel GP1BA variant (p.Arg127Gln) affecting the LRR5 domain of GPIbα in a boy with easy bruising and laboratory test results suggestive of PT-VWD. We thus aimed to investigate the impact of the p.Arg127Gln variant on GPIbα affinity for VWF and GPIbα structure. Chinese hamster ovary cells expressing p.Arg127Gln GPIbα showed increased binding of VWF induced by ristocetin and enhanced tethering on immobilized VWF as compared with cells expressing wild-type GPIbα. Surface plasmon resonance confirmed that p.Arg127Gln enhances the binding affinity of GPIbα for VWF. Hydrogen-deuterium exchange mass spectrometry showed that p.Arg127Gln of LRR, while having little effect on the dynamics of the LRR locally, enhances the conformational dynamics of the GPIbα C-terminal disulfide loop structure. Our data demonstrate for the first time that GOF variants outside the GPIbα C-terminal disulfide loop may be pathogenic and that aminoacidic changes in the LRR may cause allosterically conformational changes in the C-terminal disulfide loop of GPIbα, inducing a conformation with high affinity for VWF.
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Uesugi, Y., J. Arima, M. Iwabuchi, and T. Hatanaka. "C-terminal loop of Streptomyces phospholipase D has multiple functional roles." Protein Science 16, no. 2 (December 22, 2006): 197–207. http://dx.doi.org/10.1110/ps.062537907.
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Yano, Yoshiaki, Takuya Shimbo, Yukihiko Sugimoto, and Katsumi Matsuzaki. "Intracellular third loop–C-terminal tail interaction in prostaglandin EP3β receptor." Biochemical and Biophysical Research Communications 371, no. 4 (July 2008): 846–49. http://dx.doi.org/10.1016/j.bbrc.2008.04.180.
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Goch, G., H. Kozłowska, A. Wójtowicz, and A. Bierzyński. "A comparative CD and fluorescence study of a series of model calcium-binding peptides." Acta Biochimica Polonica 46, no. 3 (September 30, 1999): 673–77. http://dx.doi.org/10.18388/abp.1999_4139.
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Lanthanide-saturated peptides analogous to calcium-binding loops of EF-hand proteins can be used to stabilize the alpha-helical structure of peptide or protein segments attached to their C-termini. To study conformational properties of such loop-containing hybrids it is necessary to produce them in bacteria. In peptides obtained in this way the helix will be destabilized by the negatively charged C-terminal alpha-carboxyl groups. We propose to block them by the homoserine lactone. The results presented in this paper indicate that the presence of the lactone even at the C-terminus of the loop does not have any negative effect on the loop helix-nucleation ability. On the other hand, the presence of the alpha-NH3+ at the loop N-terminus leads to a drop of metal-binding constant and loss of the rigid structure of the alpha-helical segment of the loop. The alpha-amino group separated by one glycine residue from the loop N-terminus should also be avoided because it perturbs the conformation of the N-terminal part of the loop and may reduce the loop affinity to lanthanide ions.
Dissertations / Theses on the topic "C-terminal loop"
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Guo, Xiangxue. "Biochemical and Bioinformatics Analysis of CVAB C-Terminal Domain." Digital Archive @ GSU, 2006. http://digitalarchive.gsu.edu/biology_diss/3.
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Cytoplasmic membrane proteins CvaB and CvaA and the outer membrane protein TolC form the bacteriocin colicin V (ColV) secretion system in Escherichia coli. CvaB functions as an ATP-binding cassette transporter with nucleotide-binding motifs in the C-terminal domain (CTD). To study the role of CvaB-CTD in the ColV secretion, a truncated construct of this domain was made and over-expressed. Different forms of CvaB-CTD were obtained during purification, and were identified as monomer, dimer, and oligomer on gel filtration. Nucleotide binding was shown critical for the CvaB-CTD dimerization: oligomers could be converted into dimers by nucleotide bindings; the removal of nucleotide from dimers resulted in transient monomers followed by CTD oligomerization and aggregation; no dimer form could be cross-linked from the nucleotide-binding deficient mutant D654H. The spatial proximity of the Walker A site and ABC signature motif in CTD dimer was identified through disulfide cross-linking of mixed CvaB-CTD with mutants A530C and L630C, while mutations did not dimerize individually. Those results indicated that the CvaB-CTD formed a nucleotide-dependent head-to-tail dimer. Molecular basis of differential nucleotide bindings was also studied through bioinformatics prediction and biochemical verification. Through sequence alignment and homology modeling with bound ATP or GTP, it was found that the Ser503 and Gln504 on aromatic stacking region (Y501DSQ-loop) of CvaB-CTD provided two additional hydrogen-bonds to GTP, but not to ATP. Site-directed mutations of the S503A and/or Q504L were designed based on the model. While site-directed mutagenesis studies of Walker A&B sites or the ABC signature motif affected little on the GTP-binding preference, the double mutation (S503A/Q504L) on the Y501DSQ-loop increased both ATP-binding and ATPase activity at low temperatures. The double mutant showed slight decrease of GTP-binding and about 10-fold increase of the ATP/GTP-binding ratio. Similar temperature sensitivity in nucleotide-binding and activity assays were identified in the double mutant at the same time. Mutations on the Y501DSQ-loop did not affect the ColV secretion level in vivo. Together, the Y501DSQ-loop is structurally involved in the differential binding of GTP over ATP.
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Reincke, Momsen [Verfasser]. "Inactivation and anion selectivity of volume-regulated anion channels depend on C-terminal residues of the first extracellular loop / Momsen Reincke." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2017. http://d-nb.info/1140486772/34.
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Lin, Po-Yu, and 林柏宇. "Role of the SWI5 C-terminal loop in SWI5-SFR1c complex interaction with RAD51." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/95275546855885361965.
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碩士國立清華大學
生物資訊與結構生物研究所
104
SWI5-SFR1 protein complex (S5S1) has been proven as an accessory factor of homologous recombination repair, which can restore the DNA double strands break (DSB). When DNA double strands break (DSB) happen, RAD51 recombinases (RAD51) as a key protein form a presynaptic filament via binding to a single-stranded DNA. Then, ATP would bind to RAD51 to stabilize the RAD51-DNA complex and induce single-stranded DNA exchange. Due to the hydrolytic activity of RAD51, ATP would be hydrolyzed to ADP and the activity of RAD51-DNA complex will decrease, and S5S1 can promote the ADP releasing rate by interaction between RAD51. Recently, two active sites, F83 and L85, on the C-terminus of SWI5 (S5) have been reported to participate in the interaction between S5S1 and RAD51. In order to investigate their interaction, we use molecular modeling with the template “S5S1c from yeast (which has a known crystal structure, PDB code: 3VIQ)” to construct the model, we found that S5F83 and S5L85 are located in the hydrophobic core in the ending of S5 and faced inside the core. Hence, we speculate the two positions would expose and attach to RAD51 when the bundle structure on the S5 C-terminal alpha-helix was separated. To validate our hypothesis, first, we fix the C-terminal loop by creating the disulfide bond S5D89C-S1C53 on the complex. In addition, to prevent the other disulfide bond take place in the molecular, we also replaced the S1C59 to Ser. Next, we compared the secondary and tertiary structure by circular dichroism (CD) and small-angle X-ray scattering (SAXS). CD analysis showed that both S5S1c and S5D89CS1cC59S presented mainly alpha-helical structure, and their secondary structure compositions are similar by analyzed on the DichroWEB website. For SAXS experiment, we determined the structure characteristic of S5S1c and mutant, and constructed the ab initio model of them. The results showed no huge difference between S5S1c and mutant. Finally, the binding ability was determined by pull-down assay. We compared S5S1c, loop-fixed and unfixed S5D89CS1cC59S (without and with 2-ME treatment) The results showed that, compare to S5S1c, loop-fixed S5D89CS1cC59S cannot interact to RAD51, and it restored partially binding ability when freed the loop which indicate S5F83 and S5L85 could expose and bind to RAD51. In conclusion, we speculate the opening of S5 C-terminal loop is essential when S5S1c interact to RAD51. Our study provide information regarding to S5S1c binding to RAD51.
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Hsu, Po-Hung, and 徐鉑泓. "Use Proximity-dependent biotinylation to identify C-terminal interacting proteins of mouse Cryptochrome 1 and to characterize their roles in the regulation of transcription-translation feedback loop of circadian clock." Thesis, 2019. http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22107NCHU5107005%22.&searchmode=basic.
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碩士國立中興大學
生物化學研究所
107
CRY is an important transcriptional regulator in the transcription-translation feedback loop of circadian rhythm. In mammalian cells, CRY transcription is activated by the CLOCK::BMAL1 transcription factor, and the production protein CRY can alone or form a heterodimer with another protein PER to repress the transcriptional activty of the circadian rhythm core proteins CLOCK and BMAL1 to achieve the feedback mechanism. CRY is one of a photolyase/cryptochrome family protein. The main difference from other member proteins is the sequence and length of the C-terminus. The major different from CRY1 and CRY2 in mouse and human is also the sequence at the C-terminus. It is known that the deletion of the C-terminal sequence does not affect the ability of CRY to repress CLOCK::BMAL1 complex, but its research is very limited. We hope to utilize the identification C-terminal interaction proteins to explore their effects on CRY1. The Biotin Labeling System (BioID) uses engineered biotin ligase to activate biotin to label surrounding proteins. The advantage is that the affinity of biotin and avidin enables the interacting proteins to be purified under the stronger conditions. In HEK293T cells, we expressed this biotin ligase at the C-terminus of CRY1 and Confirm the biotin ligase activity of the fusion protein. Then using the Dual-Luciferase Assay to confirm the CRY1 maintained the activity of repressing CLOCK::BMAL1 after BioID binding to C-terminus. And then using this fusion protein to express in the CPN_KO cells which deficient in CRY, PER and NR1D genes to rule out possible indirect affects. By using the detection of biotin-labeled proteins and qPCR to analysis the CLOCK: BMAL downstream gene Dbp expression to confirmed that the mark of the intracellular fusion protein and the activity of the transcriptional repressor still exist. At present, it is possible to label peripheral proteins near to CRY1 using BioID method by cell nuclear fraction treatment, and to distinguish many different kinds and sizes of proteins with a certain binding ability. And then, this protein will be further analyzed and purified as a target, and analyzed by mass spectrometry to study the interaction of its protein with CRY1 and its identity.
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Wang, Chih-Chieh, and 王志傑. "NMR Study of Streptopain: The role of the catalytic and C-terminal Loops in its Inhibitor Binding and Protease Activity." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/46708686670521161731.
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碩士國立成功大學
生物化學研究所
94
Streptopain (streptococcal pyrogenic exotoxin B; SPE B) is an extracellular cysteine protease expressed by the pathogenic bacterium Streptococcus pyogenes. SPE B is initially expressed as a 42-kDa zymogen and subsequently converted to a 28-kDa active protease by autocatalysis or proteolysis. Many reports have shown that SPE B is an important virulence factor in streptococcal infection such as the dissemination, colonalization, invasion of bacteria, and inhibition of wound healing. To understand why SPE B has broad substrate specificity and to design the drugs for SPE B, we used NMR spectroscopy to determine the 3D structure and dynamics of the SPE B/inhibitor complex. Comparisons of NMR chemical shift differences between the SPE B/inhibitor complexes and the C47S mutant showed that six regions, including Y15-G18, T45-A51, S135-S141, G188-F197, W212-W214, and A231-A246, were involved in the binding of inhibitors to SPE B. The result suggests that the A231-A246 loop, which is unobserved in the crystal structure, may play important roles in substrate binding and recognition. Dynamics analysis of the SPE B/E-64, SPE B/E-64c, and SPE B/IAA complexes showed that the catalytic (G188-F197) and C-terminal (A231-G240) loops were the most flexible regions with motions on the ms/ms and ps/ns timescales. In contrast to the complexes with inhibitors containing carboxylic acid moiety, these loops of the C47S mutant and the SPE B/IAAm complex were less flexible. 3D structures of C47S mutant and SPE B/E-64 complex were determined by NMR spectroscopy. The distances between C-terminal and the catalytic loops of the C47S mutant and the SPE B/E-64 complex were 5.94 and 11.62 Å, respectively. This is consistent with NOE analysis that interactions between residues in H195 and A231, and in V192 and A238 were observed in the C47S mutant. Our mutagenesis study also showed that mutations on V189, the residue of the catalytic loop, and on G239, the residue of the C-terminal loop, caused an 11- to 61-fold decrease in activity, suggesting that they were important for the substrate binding. In this study, we found that not only the catalytic loop but also the C-terminal loop play and an important role in the substrate binding and enzyme catalysis of SPE B. We also found that the S135-S141 and W212-W214 loops, the conserved regions in the papain superfamily, have conformational exchange with high Rex values. Based on 15N/13C-edited and -filtered experiments, the NOE interactions indicated that G136 of the S135-S141 loop interacts with the inhibitor, E-64. The conformation of E-64 will be docked into 3D structure of SPE B with the observed intermolecular NOEs. These finding indicates that the C-terminal and the catalytic loops of SPE B play an important role in its substrate binding, and the results will facilitate rational drug design of SPE B.
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Baalmann, Elisabeth. "Physiologische und strukturelle Untersuchungen zur Redoxmodulation, Aggregation/Dissoziation und Coenzymspezifität der NAD(P)(H)-Glycerinaldehyd-3-Phosphat Dehydrogenase." Doctoral thesis, 2004. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2004070814.
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Die in dieser Arbeit durchgeführten Untersuchungen dienten dazu, die Eigenschaften und Grundlagen zur Regulation der chloroplastidären NAD(P)(H)-GAPDH im Wechsel zwischen Licht- und Dunkelmetabolismus aufzuklären. Dazu wurden Untersuchungen mit dem System ‘isoliertes Enzym’ und dem System ‘isolierte Chloroplasten’ durchgeführt. Durch die Herstellung proteolysierter NAD(P)(H)-GAPDH und rekombinanter Untereinheiten GapAM, GapBM und GapBMDC, sowie gleichzeitig exprimierter GapAMBM und GapAMBMDC war die Möglichkeit geschaffen, die Funktion der CTE bei der Regulation zu untersuchen. Eigenschaften von NAD(H)-abhängiger plastidärer GapCp konnten mit angereinigtem und rekombinant hergestelltem Enzym aus roter Paprikafrucht ermittelt werden.
Regulation von NAD(P)(H)-GAPDH im isolierten intakten Chloroplasten aus Spinat
Durch Reduktion von NAD(P)(H)-GAPDH in belichteten isolierten intakten Spinatplastiden, vermutlich durch Thioredoxinf, ist das Enzym sensitiver gegenüber 1,3bisPGA, da der Ka-Wert von 17-21 µM auf ca. 1-2 µM gesenkt wird. Die gleichzeitig steigende Konzentration von 1,3bisPGA auf ca. 0,8 µM im Chloroplasten führt zur Aktivierung und damit verbundener Dissoziation des Enzyms. Die Aktivierung betrifft ausschließlich die NADPH-abhängigen Aktivitäten. NADPH, NADP und ATP scheiden als Aktivatoren in vivo aus, da sie bei im Chloroplasten im Licht und im Dunkeln herrschenden Konzentrationen von 140 µM NAD das Enzym nicht aktivieren und unphysiologisch hohe Konzentrationen der Effektoren zur Aktivierung des Enzyms benötigt würden. Die Inaktivierung im Dunkeln erfolgt durch Absenkung der 1,3bisPGA-Konzentration, und das Enzym wird durch ein bislang nicht bekanntes Oxidationsmittel oxidiert. NAD, sowie möglicherweise auch GAP und NADH sind an der Inaktivierung und gleichzeitigen Aggregation beteiligt.
Die CTE der Untereinheit B ist für die Aggregation/Dissoziation von NAD(P)(H)-GAPDH verantwortlich
Im Vergleich von NAD(P)(H)-GAPDH-Isoenzymen besitzt ausschließlich GapB aus Chloroplasten höherer Pflanzen eine CTE von 28-32 Aminosäuren Länge. Sie ist gekennzeichnet durch zwei konservierte Cysteine, zwischen denen sich acht Aminosäuren befinden. In der Mitte dieser acht Aminosäuren befindet sich ein Prolin, welches u.a. für den Richtungswechsel bei der Faltung eines Proteins verantwortlich ist, so dass sich zwischen den beiden Cysteinen eine Disulfidbrücke ausbilden könnte. Die CTE aus Spinat besitzt außerdem einen hohen Anteil von sieben negativ geladenen Aminosäuren. In Rahmen dieser Arbeit wurde ein Modell enwickelt, welches beinhaltet, dass die Aggregation von vier (A2B2)-Tetrameren über Salzbrückenbindung negativ geladener Aminosäuren der CTE und nach außen exponierten positiv geladenen Aminosäuren von GapA vermittelt wird. Ergebnisse mit NAD(P)(H)-GAPDH, der die CTE fehlt, d.h. proteolysierte NAD(P)(H)-GAPDH und rekombinant hergestellte GapAM, GapBMDC und GapAMBMDC bestätigen das Modell. Die drei tetrameren Formen, sowie die gleichzeitig exprimierte GapAMBMDC sind nicht fähig, zu aggregieren. Ausschließlich GapB und die gleichzeitig exprimierte GapAMBMC aggregieren in eine hochmolekulare Form von ca. 470 kDa, bzw. eine Mischung von 470 und 300 kDa.
Die CTE der Untereinheit B ist für die Redoxmodulation von NAD(P)(H)-GAPDH verantwortlich.
NAD(P)(H)-GAPDH höherer Pflanzen besitzt fünf konservierte Cysteine: 18, 149, 153, 274 und 285, wovon sich Cystein 149 und Cystein 153 im aktiven Zentrum befinden. Cystein 153 in nicht an der Katalyse beteiligt. In der CTE von GapB sind zusätzlich zwei Cysteine 355 und 364 konserviert. Im Rahmen dieser Arbeit konnte gezeigt werden, dass die lange Zeit
prognostizierte intramolekulare Disulfidbrücke zwischen Cystein 18 und 285 nicht vorhanden ist. Dies ergibt sich aus der Tatsache, dass in Algen, deren NAD(P)(H)-GAPDH als redoxmoduliert beschrieben ist, Cystein 285 nicht vorkommt. Weiterhin zeigen eigene Ergebnisse, dass NAD(P)(H)-GAPDH, der die CTE fehlt, d.h. proteolysierte NAD(P)(H)-GAPDH, rekombinant hergestellte GapAM und GapBMDC, weder durch DTTred noch in Kombination mit 1,3bisPGA aktiviert werden. Die tetrameren Formen sind nicht redoxmoduliert. Daraus wird gefolgert, dass die für die Redoxmodulation verantwortliche Disulfidbrücke sich in der CTE von GapB befindet.
Die CTE der Untereinheit B ist für die Nucleotidspezifität von NAD(P)(H)-GAPDH verantwortlich
Die Bindung von NADPH, bzw. NADH in den verschiedenen Isoenzymen von NAD(P)(H)-GAPDH hängt von der Aminosäurezusammensetzung in den Positionen 32, 33, 187 und 188 ab. Die Aminosäuren 187 und 188 befinden sich auf einem S-loop, der in das aktive Zentrum eines benachbarten Monomers hineinreicht und mit ihm eine funktionelle Einheit bildet. NAD(H) wird in den Positionen 32 und 33 gebunden; eine Bindung von NADP(H) ist durch sterische Hinderung und Ladung des Prolins 188, welches in cytosolischer NAD(H)-GAPDH vorkommt, nicht möglich. Da chloroplastidäre NAD(P)(H)-GAPDH in der Position 188 ein Serin besitzt, kann die Phosphatgruppe von NADP(H) binden. Aufgrund der Affinitäten der inaktiven 600 kDa- und aktiven 150 kDa-NAD(P)(H)-GAPDH für NADPH, bzw. der in Chloroplasten im Licht wie im Dunkeln herrschenden NADPH-Konzentrationen, wäre es theoretisch möglich, dass das Coenzym sowohl bei Belichtung als auch im Dunkeln umgesetzt wird. Während des Licht-Dunkel-Übergangs wechselt das Enzym jedoch zwischen dem Coenzym NADPH und NAD. In dieser Arbeit konnte anhand eines Modells aufgezeigt werden, dass im Dunkel-adaptierten Chloroplasten die Bindung von NADPH an der Aminosäure 188 unterbunden ist, da der S-loop um einige A aus dem aktiven Zentrum gezogen wird. Ursache dafür ist mit großer Wahrscheinlichkeit die CTE, die in der 600 kDa-Form an positiv geladenen Aminosäuren des S-loops bindet.
Die Aktivierung von NAD(P)(H)-GAPDH in struktureller Hinsicht.
Die 600 kDa-Form von NAD(P)(H)-GAPDH ist mit dem Coenzym NADPH inaktiv, da sich innerhalb der CTE eine Disulfidbrücke gebildet hat. Die strukturelle Änderung der CTE erlaubt es, dass negativ geladenene Aminosäuren der CTE an nach außen exponierten positiv geladenen Aminosäuren eines S-loops von GapA binden können. Dadurch ist eine Bindung von NADPH im aktiven Zentrum an den S-loop nicht möglich. NAD kann ungehindert binden. Bei einsetzender Belichtung wird die Disulfidbrücke der CTE aufgebrochen, ohne dass das Enzym dissoziert. Mit steigenden Konzentrationen von dreifach negativ geladenem 1,3bisPGA wird die Salzbrückenbindung zwischen der CTE und dem S-loop gelöst, so dass NAD(P)(H)-GAPDH in vier Tetramere dissoziiert und gleichzeitig NADPH umsetzen kann.
Book chapters on the topic "C-terminal loop"
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Inglis, Adam S., John F. K. Wilshire, Franca Casagranda, and Robert L. Laslett. "C-terminal Sequencing: A New Look at the Schlack-Kumpf Thiocyanate Degradation Procedure." In Methods in Protein Sequence Analysis, 137–44. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-73834-0_18.
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Opella, S. J., and L. E. Chirlian. "A Solid-State NMR Approach to Structure Determination of Membrane-Associated Peptides and Proteins." In Biological NMR Spectroscopy. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195094688.003.0017.
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Structural biology relies on detailed descriptions of the three-dimensional structures of peptides, proteins, and other biopolymers to explain the form and function of biological systems ranging in complexity from individual molecules to entire organisms. NMR spectroscopy and X-ray crystallography, in combination with several types of calculations, provide the required structural information. In recent years, the structures of several hundred proteins have been determined by one or both of these experimental methods. However, since the protein molecules must either reorient rapidly in samples for multidimensional solution NMR spectroscopy or form high quality single crystals in samples for X-ray crystallography, nearly all of the structures determined up to now have been of the soluble, globular proteins that are found in the cytoplasm and periplasmof cells and fortuitously have these favorable properties. Since only a minority of biological properties are expressed by globular proteins, and proteins, in general, have evolved in order to express specific functions rather than act as samples for experimental studies, there are other classes of proteins whose structures are currently unknown but are of keen interest in structural biology. More than half of all proteins appear to be associated with membranes, and many cellular functions are expressed by proteins in other types of supramolecular complexes with nucleic acids, carbohydrates, or other proteins. The interest in the structures of membrane proteins, structural proteins, and proteins in complexes provides many opportunities for the further development and application of NMR spectroscopy. Our understanding of polypeptides associated with lipids in membranes, in particular, is primitive, especially compared to that for globular proteins. This is largely a consequence of the experimental difficulties encountered in their study by conventional NMR and X-ray approaches. Fortunately, the principal features of two major classes of membrane proteins have been identified from studies of several tractable examples. Bacteriorhodopsin (Henderson et al., 1990), the subunits of the photosynthetic reaction center (Deisenhofer et al., 1985), and filamentous bacteriophage coat proteins (Shon et al., 1991; McDonnell et al., 1993) have all been shown to have long transmembrane hydrophobic helices, shorter amphipathic bridging helices in the plane of the bilayers, both structured and mobile loops connecting the helices, and mobile N- and C-terminal regions.
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Drijfhout, Jan W., and Peter Hoogerhout. "Methods of preparing peptide—carrier conjugates." In Fmoc Solid Phase Peptide Synthesis. Oxford University Press, 1999. http://dx.doi.org/10.1093/oso/9780199637256.003.0014.
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For many applications, peptides should be conjugated to carriers. An important example is the conjugation of peptides to proteins, carbohydrates, or lipids for immunological studies. Further examples are the preparation of peptide affinity media and the conjugation of peptides to suitable coating compounds on surfaces for enzyme-linked immunosorbent assay and plasma resonance. The most important consideration in designing conjugates is that the peptide part of the conjugate must retain its biological activity. This means that the site of activity of the peptide must not be involved in the conjugation reaction. However, the active part of the peptide is often not precisely known, which complicates the design of a proper conjugation strategy. In addition, if the peptide is a fragment of a larger biologically active protein, the small peptide will frequently not adopt the conformation (for instance, a loop structure) of the corresponding sequence in the native protein. This might also abolish desired biological properties, such as the possibility to induce functional antibodies recognizing the native protein. In that case, appropriate artificial conformational restrictions should be introduced into the peptide - if possible. From the numerous conjugation methods available, only a few are described in this chapter. One example concerns the application of the homobifunctional cross-linker glutaraldehyde. Heterobifunctional cross-linking is illustrated by coupling of thiol-containing peptides or carriers to sulphydryl-reactive carriers or peptides, respectively. A general and easy method of conjugating peptides to proteins is to make use of homobifunctional cross-linkers. An example of a homobifunctional cross-linker is glutaraldehyde. This bis-aldehyde reacts with amine groups at neutral or basic pH to yield enamines, which can be reduced optionally to amines with sodium cyanoborohydride. The peptide and the protein react selectively via their N-terminus and/or lysine side chains to give not only a very complex mixture of products—peptide-peptide, peptide-protein, and protein-protein conjugates—but also large constructs containing peptide and protein. Typically, several peptide molecules per protein molecule are coupled. In view of the complex reaction pathway, the batch-to-batch reproducibility of the conjugate is difficult to control. If the peptide contains a lysine in the active part, it is recommended to extend the peptide N- or C-terminally with some additional lysines during synthesis in order to provide more amine groups for conjugation.
Conference papers on the topic "C-terminal loop"
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Hijikata-Okunomiya, A., S. Okamoto, R. Kikumoto, and Y. Tamao. "STEREOGEOMETRY OP THE ACTIVE SITES OF SERINE ENZYMES GATHERED FROM SYNTHETIC THROMBIN-INHIBITORS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644606.
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MD-805 is a potent thrombin-inhibitor having the structure of tri-pods; Arg skeletone, N-terminal side and C-terminal side. MD-805 showed weaker inhibitory activity to other enzymes than thrombin. In this report, to gather more detailed informations about the structural features of serine enzymes concerning the specificity, we experimentally examined the structure-activity relationship (SAR) of a number of arginine derivatives including MD-805 and theoretically generated a MD-805-trypsin complex model using the results of X-ray crystallography of MD-805 and BPTI-trypsin complex by calculation in principle to minimize van der Waals contacts, and thus we discussed to interpret SAR from the molecular level. SAR of C-terminal side of arginine derivatives was obtained with the inhibitory activity to trypsin, plasmin, and glandular kallikrein and compared with the previous results of thrombin, the followings being indicated: (1) The hydrophobic binding pocket (HBP), which was reported by us to be at least partly similar in stereogeometry between trypsin and thrombin, had the depth corresponded to the length of ethylpiperidine, (2) concerning the site (termed the P site) next to HBP, there were large differences in stereogeometry between trypsin and thrombin; the P site of trypsin could accept propyl and phenyl group attached to 4-position of piperidine, while that of thrombin was unable to accept them and (3) the P sites of plasmin and glandular kallikrein resembled that of trypsin in being able to accept phenyl group. MD-805-trypsin complex model supported the reasonable understanding that the stereogeometrical similarity in HBP between thrombin and trypsin was attributable to the high homology in amino acid sequences in Ser-195 loop and that the dissimilarity in the P sites between thrombin and the others was attributable to 9 amino acids insertion found only in thrombin (Loop B). Furthermore, many dansylarginine derivatives showed very strong inhibition for pseudocholinesterase, however, SAR for C-terminal side of these derivatives revealed the similarity and dissimilarity in HBP and the P site between pseudocholinesterase and the proteases described above.
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polyphemus, Limulus, T. Muta, T. Miyata, F. Tokunaga, T. Nakamura, and S. Iwanaga. "PRIMARY STRUCTURE OF ANTI-LIPOPOLYSACCHARIDE FACTOR ISOLATED FROM AMERICAN HORSESHOE CRAB." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644608.
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In 1982, a protein component that inhibits the limulus coagulation cascade was found in the hemocyte lysates from Japanese and American horseshoe crabs and named anti-lipopolysaccharide (LPS) factor. This protein specifically inhibited the LPS-mediated activation of limulus factor C and had a strong anti-bacterial effect on the growth of Gram-negative R-type bacteria. Moreover, it had a hemolytic activity on the red blood cells sensitized with LPS.In the present study, the complete amino acid sequence of anti-LPS factor purified from the Limulus (L) polyphemus hemocytes was determined by characterization of the NH2-terminal sequence and the peptides generated after digestion of the protein with lysyl endopeptidase, clostripain, and Staphylococcus aureus V8 protease. Upon sequencing the peptides by the automated Edman method, the following primary structure was obtained:During the sequence analysis, two species of the protein, which differed from each other at one locus, were found and characterized. L. polyphemus anti-LPS factor was a basic protein consisting of a single polypeptide chain of 101 residues and a calculated molecular weight of 11,786 or 11,800. The hydrophobic NH2-terminal sequence and positive charges found in the disulfide loop yielded a typical amphipathic character of this protein. Moreover, L. polyphemus anti-LPS factor showed 83% sequence identity with the Tachypleus tridentatus protein (J. Aketagawa, et al. (1986) J. Biol. Chem. 261, 7357-7365), and the sequence similar to that observed in the EF-hand structure was found to contain in the COOH-terminal portions of these proteins, although its function is unknown.
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Verhagen, Joris, Etienne Heymans, Darko Gjorgjievski, Arjan Voogt, and Frederik Van Nuffel. "Eemshaven LNG - Repurposing an FSRU Built for Tropical Conditions to Operate in the North Sea." In Offshore Technology Conference. OTC, 2023. http://dx.doi.org/10.4043/32586-ms.
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Abstract In 2017, Exmar has taken delivery of an FSRU which was intended to operate in Bangladesh to provide the country up to 600 MMSCFD of natural gas. The FSRU was purpose-built with a shallow draft to allow it to be moored in a river estuary. The project in Bangladesh never materialized and the FSRU ended up in lay-up in Singapore. With the energy crisis unfolding early 2022 several countries in Europe urgently started investigating the possibilities to bring FSRUs to Europe to ensure the security of natural gas supplies and in order to have a back-up for the decreasing natural gas flow from Russia. It was proposed to mobilize our FSRU from Singapore and eventually a 5-year contract with Gasunie was signed. This deal made it possible to operate the FSRU at the EemsEnergy Terminal in The Netherlands. For the FSRU to operate safely and efficiently at the new terminal, several modifications needed to be applied in order to adapt the FSRU to the new, colder environment. First and foremost, the regasification system needed to be provided with warm heating water. As per the original design, the FSRU regasification system needs seawater of at least 15 °C in order to avoid freezing in the LNG vaporizers. A closed loop heating water system was not foreseen for heating the water which is used to vaporize the LNG. Several options have been investigated and together with the Client, it was decided to use heat from shore as input for vaporizing the LNG. The FSRU layout was also found incompatible with terminal layout and changes were required on the main piping system and on the mooring system. Within a couple of months time the mooring design was revisited, the main piping layout was modified to ensure the FSRU could fit the terminal and could stay safely moored in the new metocean environment. After the FSRU was mobilized from Singapore it went straight into the conversion yard in the Netherlands. Within a period of 2 months all changes were implemented and the FSRU could be deployed on time to supply LNG to The Netherlands. This project demonstrates that our FSRU concept is flexible and can be redeployed quickly to other sites when market conditions change. Thanks to our in-house engineering and operational capabilities, we could upgrade the FSRU design in a short time, matching the very demanding project timeline.
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Dahiback, Bjorn, Ake Lundwall, Andreas Hillarp, Johan Malm, and Johan Stenflo. "STRUCTURE AND FUNCTION OF VITAMIN K-DEPENDENT PROTEIN S, a cofactor to activated protein C which also interacts with the complement protein C4b-binding protein." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1642960.
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Protein S is a single chain (Mr 75.000) plasma protein. It is a cofactor to activated protein C (APC) in the regulation of coagulation factors Va and Villa. It has high affinity for negatively charged phospolipids and it forms a 1:1 complex with APC on phospholipid surfaces, platelets and on endothelial cells. Patients with heterozygous protein S deficiency have a high incidence of thrombosis. Protein S is cleaved by thrombin, which leads to a loss of calcium binding sites and of APC cofactor activity. Protein S has two to three high affinity (KD 20uM) calcium binding sites - unrelated to the Gla-region - that are unaffected by the thrombin cleavage. In human plasma protein S (25 mg/liter) circulates in two forms; free (approx. 40%) and in a 1:1 noncovalent complex (KD 1× 10-7M) with the complement protein C4b-binding protein (C4BP). C4BP (Mr 570.000) is composed of seven identical 70 kDa subunits that are linked by disulfide bonds. When visualized by electron microscopy, C4BP has a spiderlike structure with the single protein S binding site located close to the central core and one C4b-binding site on each of the seven tentacles. When bound to C4BP, protein S looses its APC cofactor activity, whereas the function-of C4BP is not directly affected by the protein S binding. Chymotrypsin cleaves each of the seven C4BP subunits close to the central core which results in the liberation of multiple 48 kDa “tentacte” fragments and the formation of a 160 kDa central core fragment. We have successfully isolated a 160 kDa central core fragment with essentially intact protein S binding ability.The primary structure of both bovine and human protein S has been determined and found to contain 635 and 634 amino acids, respectively, with 82 % homology to each other. Four different regions were distinguished; the N-terminal Gla-domain (position 1-45) was followed by a region which has two thrombin-sensitive bonds positioned within a disulfide loop. Position 76 to 244 was occupied by four repeats homologous to the epidermal growth factor (EGF) precursor. In the first EGF-domain a modified aspartic acid was identified at position 95, B-hydroxaspartic acid (Hya), and in corresponding positions in the three following EGF-domains (positions 136,178 and 217) we found B-hydroxyasparagine (Hyn). Hyn has not previously been identified in proteins. The C-terminal half of protein S (from position 245) shows no homology to the serine proteases but instead to human Sexual Hormon Binding Globulin (SHBG)(see separate abstract). To study the structure-function relationship we made eighteen monoclonal antibodies to human protein S. The effects of the monoclonals on the C4BP-protein S interaction and on the APC cofactor activity were analysed. Eight of the antibodies were calciumdependent, four of these were against the Gla-domain, two against the thrombin sensitive portion and two against the region bearing the high affinity calcium binding sites. Three of the monoclonals were dependent on the presence of chelating agents, EDTA or EGTA, and were probably directed against the high affinity calcium binding region. Three other monoclonals inhibited the protein S-C4BP interaction. At present, efforts are made to localize the epitopes to gain information about functionally important regions of protein S.
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Soares, Luigi, and Fernando Magno Quintão Pereira. "Memory-Safe Elimination of Side Channels." In Concurso de Teses e Dissertações. Sociedade Brasileira de Computação - SBC, 2023. http://dx.doi.org/10.5753/ctd.2023.229445.
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In this project, we find a new service for partial control-flow linearization (PCFL), a code transformation initially conceived to maximize work performed in vectorized programs. We show that PCFL can be employed as a defense mechanism against timing attacks. This transformation is sound: given an instance of its public inputs, the partially linearized program always runs the same sequence of instructions, regardless of secret inputs. Incidentally, if the original program is publicly safe, then accesses to the data cache will be data oblivious in the transformed code. The transformation is optimal: every branch that depends on some secret data is linearized; no branch that depends on only public data is linearized. Therefore, the transformation preserves loops that depend exclusively on public information. If every branch that leaves a loop depends on secret data, then the transformed program will not terminate. Our transformation extends previous work in non-trivial ways. It handles C constructs such as “break”, “switch” and “continue”, which are absent in the FaCT domain-specific language (2018). Like Constantine (2021), our code transformation ensures operation invariance, but without requiring profiling information. Additionally, in contrast to SC-Eliminator (2018), our implementation handles programs containing general, unbounded loops.
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Soukup, Todd J., and Vincent P. Heuring. "Implementation of a Fiber Optic Delay Line Memory." In Optical Computing. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/optcomp.1991.me14.
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The objective of the Digital Optical Computer (DOC) group at the University of Colorado at Boulder is to implement a general purpose computer using the speed advantages of light.[1] The machine is being implemented using lithium niobate directional couplers as logic elements and optical fiber loops for memory. Figure 1 shows the logic functionality of the directional coupler. Terminal C, normally an electronic input, has been converted to an optical input by the addition of a sensitive detector, amplifier, and thresholder.[2] This paper describes the implementation of the fiber optic delay line memory.
Reports on the topic "C-terminal loop"
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Rafaeli, Ada, Russell Jurenka, and Chris Sander. Molecular characterisation of PBAN-receptors: a basis for the development and screening of antagonists against Pheromone biosynthesis in moth pest species. United States Department of Agriculture, January 2008. http://dx.doi.org/10.32747/2008.7695862.bard.
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The original objectives of the approved proposal included: (a) The determination of species- and tissue-specificity of the PBAN-R; (b) the elucidation of the role of juvenile hormone in gene regulation of the PBAN-R; (c) the identificationof the ligand binding domains in the PBAN-R and (d) the development of efficient screening assays in order to screen potential antagonists that will block the PBAN-R. Background to the topic: Moths constitute one of the major groups of pest insects in agriculture and their reproductive behavior is dependent on chemical communication. Sex-pheromone blends are utilised by a variety of moth species to attract conspecific mates. In most of the moth species sex-pheromone biosynthesis is under circadian control by the neurohormone, PBAN (pheromone-biosynthesis-activating neuropeptide). In order to devise ideal strategies for mating disruption/prevention, we proposed to study the interactions between PBAN and its membrane-bound receptor in order to devise potential antagonists. Major conclusions: Within the framework of the planned objectives we have confirmed the similarities between the two Helicoverpa species: armigera and zea. Receptor sequences of the two Helicoverpa spp. are 98% identical with most changes taking place in the C-terminal. Our findings indicate that PBAN or PBAN-like receptors are also present in the neural tissues and may represent a neurotransmitter-like function for PBAN-like peptides. Surprisingly the gene encoding the PBAN-receptor was also present in the male homologous tissue, but it is absent at the protein level. The presence of the receptor (at the gene- and protein-levels), and the subsequent pheromonotropic activity are age-dependent and up-regulated by Juvenile Hormone in pharate females but down-regulated by Juvenile Hormone in adult females. Lower levels of pheromonotropic activity were observed when challenged with pyrokinin-like peptides than with HezPBAN as ligand. A model of the 3D structure of the receptor was created using the X-ray structure of rhodopsin as a template after sequence alignment of the HezPBAN-R with several other GPCRs and computer simulated docking with the model predicted putative binding sites. Using in silico mutagenesis the predicted docking model was validated with experimental data obtained from expressed chimera receptors in Sf9 cells created by exchanging between the three extracellular loops of the HezPBAN-R and the Drosophila Pyrokinin-R (CG9918). The chimera receptors also indicated that the 3ʳᵈ extracellular loop is important for recognition of PBAN or Diapause hormone ligands. Implications: The project has successfully completed all the objectives and we are now in a position to be able to design and screen potential antagonists for pheromone production. The successful docking simulation-experiments encourage the use of in silico experiments for initial (high-throughput) screening of potential antagonists. However, the differential responses between the expressed receptor (Sf9 cells) and the endogenous receptor (pheromone glands) emphasize the importance of assaying lead compounds using several alternative bioassays (at the cellular, tissue and organism levels). The surprising discovery of the presence of the gene encoding the PBAN-R in the male homologous tissue, but its absence at the protein level, launches opportunities for studying molecular regulation pathways and the evolution of these GPCRs. Overall this research will advance research towards the goal of finding antagonists for this important class of receptors that might encompass a variety of essential insect functions.