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Allosteric disulphide

Robin W Carrell, Randy J Read
The adaptation of the serpin framework and its mechanism to perform diverse functions is epitomised in the hormone carriers of the blood. Thyroxine and the corticosteroids are transported bound in a 1:1 ratio on almost identical sites in the two homologous binding-globulins, TBG and CBG. Recent structural findings show an equilibrated, rather than on-and-off, release of the hormones from the carriers, reflecting small reversible movements of the hinge region of the reactive loop that modify the conformational flexibility of the underlying hormone-binding site...
February 2017: Seminars in Cell & Developmental Biology
Cécile Mathieu, Linh-Chi Bui, Emile Petit, Iman Haddad, Onnik Agbulut, Joelle Vinh, Jean-Marie Dupret, Fernando Rodrigues-Lima
Dithiocarbamates (DTCs) are important industrial chemicals used extensively as pesticides and in a variety of therapeutic applications. However, they have also been associated with neurotoxic effects and in particular with the development of Parkinson-like neuropathy. Although different pathways and enzymes (such as ubiquitin ligases or the proteasome) have been identified as potential targets of DTCs in the brain, the molecular mechanisms underlying their neurotoxicity remain poorly understood. There is increasing evidence that alteration of glycogen metabolism in the brain contributes to neurodegenerative processes...
February 3, 2017: Journal of Biological Chemistry
Fatima El-Assaad, Steven A Krilis, Bill Giannakopoulos
The antiphospholipid syndrome (APS) is an autoimmune disease characterised by a procoagulant state that predisposes to recurrent thrombosis and miscarriages. Two major discoveries have advanced our understanding of the underlying complex pathogenesis of the APS. The first was the discovery that beta-2 glycoprotein-1 (β2GPI) is the major auto antigen in APS. The second was the discovery in more recent years that β2GPI contains allosteric disulphide bonds susceptible to posttranslational modification that may be involved in the development of autoantibodies in APS...
2016: Thrombosis Journal
Cécile Mathieu, Romain Duval, Angélique Cocaign, Emile Petit, Linh-Chi Bui, Iman Haddad, Joelle Vinh, Catherine Etchebest, Jean-Marie Dupret, Fernando Rodrigues-Lima
Brain glycogen and its metabolism are increasingly recognized as major players in brain functions. Moreover, alteration of glycogen metabolism in the brain contributes to neurodegenerative processes. In the brain, both muscle and brain glycogen phosphorylase isozymes regulate glycogen mobilization. However, given their distinct regulatory features, these two isozymes could confer distinct metabolic functions of glycogen in brain. Interestingly, recent proteomics studies have identified isozyme-specific reactive cysteine residues in brain glycogen phosphorylase (bGP)...
November 11, 2016: Journal of Biological Chemistry
Iván O Rivera-Torres, Tony B Jin, Martine Cadene, Brian T Chait, Sébastien F Poget
Due to their central role in essential physiological processes, potassium channels are common targets for animal toxins. These toxins in turn are of great value as tools for studying channel function and as lead compounds for drug development. Here, we used a direct toxin pull-down assay with immobilised KcsA potassium channel to isolate a novel KcsA-binding toxin (called Tx7335) from eastern green mamba snake (Dendroaspis angusticeps) venom. Sequencing of the toxin by Edman degradation and mass spectrometry revealed a 63 amino acid residue peptide with 4 disulphide bonds that belongs to the three-finger toxin family, but with a unique modification of its disulphide-bridge scaffold...
April 5, 2016: Scientific Reports
Kody J Moleschi, Madoka Akimoto, Giuseppe Melacini
Allostery is a ubiquitous mechanism to control biological function and arises from the coupling of inhibitory and binding equilibria. The extent of coupling reflects the inactive vs active state selectivity of the allosteric effector. Hence, dissecting allosteric determinants requires quantification of state-specific association constants. However, observed association constants are typically population-averages, reporting on overall affinities but not on allosteric coupling. Here we propose a general method to measure state-specific association constants in allosteric sensors based on three key elements, i...
August 26, 2015: Journal of the American Chemical Society
Hyunjoo Cha-Molstad, Ki Sa Sung, Joonsung Hwang, Kyoung A Kim, Ji Eun Yu, Young Dong Yoo, Jun Min Jang, Dong Hoon Han, Michael Molstad, Jung Gi Kim, Yoon Jee Lee, Adriana Zakrzewska, Su-Hyeon Kim, Sung Tae Kim, Sun Yong Kim, Hee Gu Lee, Nak Kyun Soung, Jong Seog Ahn, Aaron Ciechanover, Bo Yeon Kim, Yong Tae Kwon
We show that ATE1-encoded Arg-transfer RNA transferase (R-transferase) of the N-end rule pathway mediates N-terminal arginylation of multiple endoplasmic reticulum (ER)-residing chaperones, leading to their cytosolic relocalization and turnover. N-terminal arginylation of BiP (also known as GRP78), protein disulphide isomerase and calreticulin is co-induced with autophagy during innate immune responses to cytosolic foreign DNA or proteasomal inhibition, associated with increased ubiquitylation. Arginylated BiP (R-BiP) is induced by and associated with cytosolic misfolded proteins destined for p62 (also known as sequestosome 1, SQSTM1) bodies...
July 2015: Nature Cell Biology
C L Smith, C M Shah, N Kamaludin, M P Gordge
INTRODUCTION: Cell surface thiol isomerase enzymes, principally protein disulphide isomerase (PDI), have emerged as important regulators of platelet function and tissue factor activation via their action on allosteric disulphide bonds. Allosteric disulphides are present in other haemostasis-related proteins, and we have therefore investigated whether thiol isomerase inhibition has any influence on two endothelial activities relevant to haemostatic regulation, namely activation of protein C and activation of plasminogen, with subsequent fibrinolysis...
April 2015: Thrombosis Research
Manuel Correia, Torben Snabe, Viruthachalam Thiagarajan, Steffen Bjørn Petersen, Sara R R Campos, António M Baptista, Maria Teresa Neves-Petersen
Activation of plasminogen to its active form plasmin is essential for several key mechanisms, including the dissolution of blood clots. Activation occurs naturally via enzymatic proteolysis. We report that activation can be achieved with 280 nm light. A 2.6 fold increase in proteolytic activity was observed after 10 min illumination of human plasminogen. Irradiance levels used are in the same order of magnitude of the UVB solar irradiance. Activation is correlated with light induced disruption of disulphide bridges upon UVB excitation of the aromatic residues and with the formation of photochemical products, e...
2015: PloS One
Wen-Shan Zhao, Jin Wang, Xiao-Juan Ma, Yang Yang, Yan Liu, Li-Dong Huang, Ying-Zhe Fan, Xiao-Yang Cheng, Hong-Zhuan Chen, Rui Wang, Ye Yu
Channel gating in response to extracellular ATP is a fundamental process for the physiological functions of P2X receptors. Here we identify coordinated allosteric changes in the left flipper (LF) and dorsal fin (DF) domains that couple ATP-binding to channel gating. Engineered disulphide crosslinking or zinc bridges between the LF and DF domains that constrain their relative motions significantly influence channel gating of P2X4 receptors, confirming the essential role of these allosteric changes. ATP-binding-induced alterations in interdomain hydrophobic interactions among I208, L217, V291 and the aliphatic chain of K193 correlate well with these coordinated relative movements...
2014: Nature Communications
Kaihua Zhang, Jin Zhang, Zhan-Guo Gao, Dandan Zhang, Lan Zhu, Gye Won Han, Steven M Moss, Silvia Paoletta, Evgeny Kiselev, Weizhen Lu, Gustavo Fenalti, Wenru Zhang, Christa E Müller, Huaiyu Yang, Hualiang Jiang, Vadim Cherezov, Vsevolod Katritch, Kenneth A Jacobson, Raymond C Stevens, Beili Wu, Qiang Zhao
P2Y receptors (P2YRs), a family of purinergic G-protein-coupled receptors (GPCRs), are activated by extracellular nucleotides. There are a total of eight distinct functional P2YRs expressed in human, which are subdivided into P2Y1-like receptors and P2Y12-like receptors. Their ligands are generally charged molecules with relatively low bioavailability and stability in vivo, which limits our understanding of this receptor family. P2Y12R regulates platelet activation and thrombus formation, and several antithrombotic drugs targeting P2Y12R--including the prodrugs clopidogrel (Plavix) and prasugrel (Effient) that are metabolized and bind covalently, and the nucleoside analogue ticagrelor (Brilinta) that acts directly on the receptor--have been approved for the prevention of stroke and myocardial infarction...
May 1, 2014: Nature
Philip J Hogg
Protein action in nature is generally controlled by the amount of protein produced and by chemical modification of the protein, and both are often perturbed in cancer. The amino acid side chains and the peptide and disulphide bonds that bind the polypeptide backbone can be post-translationally modified. Post-translational cleavage or the formation of disulphide bonds are now being identified in cancer-related proteins and it is timely to consider how these allosteric bonds could be targeted for new therapies...
June 2013: Nature Reviews. Cancer
Kathryn L Chapman, John B C Findlay
This study involves the structural and functional properties of the recombinant melanocortin 4 receptor (MC(4)R) expressed in the HEK-293 cell line. Using co-immuno-purification approaches, the receptor appears to be an oligomer, which can be crosslinked through disulphide bonds involving a native cysteine residue (84) to give a dimeric species. This position is located near the cytosolic region of transmembrane segment 2 and it is suggested that this is an interacting interface between MC(4)R monomers. Using co-expression of the native protein and a C84A mutant, it appears that the receptor also forms higher order oligomers via alternative interfaces...
February 2013: Biochimica et Biophysica Acta
Erkan Karakas, Noriko Simorowski, Hiro Furukawa
Since it was discovered that the anti-hypertensive agent ifenprodil has neuroprotective activity through its effects on NMDA (N-methyl-D-aspartate) receptors, a determined effort has been made to understand the mechanism of action and to develop improved therapeutic compounds on the basis of this knowledge. Neurotransmission mediated by NMDA receptors is essential for basic brain development and function. These receptors form heteromeric ion channels and become activated after concurrent binding of glycine and glutamate to the GluN1 and GluN2 subunits, respectively...
July 14, 2011: Nature
Daniel M Rosenbaum, Cheng Zhang, Joseph A Lyons, Ralph Holl, David Aragao, Daniel H Arlow, Søren G F Rasmussen, Hee-Jung Choi, Brian T Devree, Roger K Sunahara, Pil Seok Chae, Samuel H Gellman, Ron O Dror, David E Shaw, William I Weis, Martin Caffrey, Peter Gmeiner, Brian K Kobilka
G-protein-coupled receptors (GPCRs) are eukaryotic integral membrane proteins that modulate biological function by initiating cellular signalling in response to chemically diverse agonists. Despite recent progress in the structural biology of GPCRs, the molecular basis for agonist binding and allosteric modulation of these proteins is poorly understood. Structural knowledge of agonist-bound states is essential for deciphering the mechanism of receptor activation, and for structure-guided design and optimization of ligands...
January 13, 2011: Nature
Lucile Graff, Petr Obrdlik, Lixing Yuan, Dominique Loqué, Wolf B Frommer, Nicolaus von Wirén
AMMONIUM TRANSPORTER (AMT) proteins are conserved in all domains of life and mediate the transport of ammonium or ammonia across cell membranes. AMTs form trimers and use intermolecular interaction between subunits to regulate activity. So far, binding forces that stabilize AMT protein complexes are not well characterized. High temperature or reducing agents released mono- and dimeric forms from trimeric complexes formed by AMT1;1 from Arabidopsis and tomato. However, in the paralogue LeAMT1;3, trimeric complexes were not detected...
February 2011: Journal of Experimental Botany
Hao Chen, Chengqi Yi, Jin Zhang, Wenru Zhang, Zhiyun Ge, Cai-Guang Yang, Chuan He
MexR functions as the primary regulator of the mexAB-oprM multidrug efflux expression in Pseudomonas aeruginosa. It has been shown that MexR senses oxidative stress by interprotomer disulphide bond formation between redox-active cysteines. This oxidation induces MexR to dissociate from the promoter DNA, thus activating the transcriptional expression of efflux pump genes. In this study, we present the crystal structure of MexR in its oxidized form at a resolution of 2.1 A. This crystal structure reveals the mechanism by which oxidative signal allosterically derepresses the MexR-controlled transcription activation...
September 2010: EMBO Reports
Colin Levy, Katharine Pike, Derren J Heyes, M Gordon Joyce, Krisztina Gabor, Hauke Smidt, John van der Oost, David Leys
Certain bacteria are able to conserve energy via the reductive dehalogenation of halo-organic compounds in a respiration-type metabolism. The transcriptional regulator CprK from Desulfitobacterium spp. induces expression of halorespiratory genes upon binding of o-chlorophenol ligands and is reversibly inactivated by oxygen through disulphide bond formation. We report crystal structures of D. hafniense CprK in the ligand-free (both oxidation states), ligand-bound (reduced) and DNA-bound states, making it the first member of the widespread CRP-FNR superfamily for which a complete structural description of both redox-dependent and allosteric molecular rearrangements is available...
October 2008: Molecular Microbiology
James A Huntington, Charles T Esmon
Thrombin participates in its own positive and negative feedback loops, and its allosteric state helps determine the hemostatic balance. Here we present the 1.8 A crystallographic structure of S195A thrombin in two conformational states: active site occupied and active site free. The active site-occupied form shows how thrombin can accommodate substrates, such as protein C. The active site-free form is in a previously unobserved closed conformation of thrombin, which satisfies all the conditions of the so-called "slow" form...
April 2003: Structure
Clare J McCleverty, Robert C Liddington
The alpha-I domain, found in the alpha-subunit of the leucocyte integrins such as alphaMbeta2 and alphaLbeta2, switches between the open and closed tertiary conformations, reflecting the high- and low-affinity ligand-binding states of the integrin that are required for regulated cell adhesion and migration. In the present study we show, by using point mutations and engineered disulphide bonds, that ligand affinity can be reduced or increased allosterically by altering the equilibrium between the closed and open states...
May 15, 2003: Biochemical Journal
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