Sandbox Reserved 954: Difference between revisions

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, Guy S. Salvesen10, James Travis11 and James C. Whisstock, THE SERPINS ARE AN EXPANDING SUPERFAMILY OF
, Guy S. Salvesen10, James Travis11 and James C. Whisstock, THE SERPINS ARE AN EXPANDING SUPERFAMILY OF
STRUCTURALLY SIMILAR BUT FUNCTIONALLY DIVERSE PROTEINS, http://www.jbc.org/content/early/2001/07/02/jbc.R100016200.full.pdf DOI : 2001/07/02/jbc.R100016200.full.pdf </ref> <ref>PDB, Crystal structure of human squamous cell carcinoma antigen 1 http://www.rcsb.org/pdb/explore/remediatedSequence.do?structureId=2ZV6&bionumber=1 DOI : pdb/explore/remediatedSequence.do?structureId=2ZV6&bionumber=1</ref> .  
STRUCTURALLY SIMILAR BUT FUNCTIONALLY DIVERSE PROTEINS, http://www.jbc.org/content/early/2001/07/02/jbc.R100016200.full.pdf DOI : 2001/07/02/jbc.R100016200.full.pdf </ref> <ref>PDB, Crystal structure of human squamous cell carcinoma antigen 1 http://www.rcsb.org/pdb/explore/remediatedSequence.do?structureId=2ZV6&bionumber=1 DOI : pdb/explore/remediatedSequence.do?structureId=2ZV6&bionumber=1</ref> .  
The most important part of Serpins is an exposed region of 20 amino acids near the C terminus named the reactive center loop (<scene name='60/604473/The_rcl_loop_scene/3'>RCL</scene>). This <scene name='60/604473/The_rcl_loop_scene/3'>RCL</scene> allow the specificity interaction of the inhibitor for the target protease<ref> PMID : PMC24842</ref>.
The most important part of Serpins is an exposed region of 20 amino acids near the C terminus named the reactive center loop (<scene name='60/604473/The_rcl_loop_scene/3'>RCL</scene>). The amino-acids of <scene name='60/604473/The_rcl_loop_scene/3'>RCL</scene> are very conservated for Serpin B3 and  allow the specificity interaction of the inhibitor for the target protease<ref> PMID : PMC24842</ref>.


[[Image:Structure region.jpg|300px]]
[[Image:Structure region.jpg|300px]]
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==Fonction==
==Fonction==


Structural studies on serpins revealed that inhibitory members of the family undergo an unusual conformational change, termed the Stressed to Relaxed (S to R) transition. During this structural transition the <scene name='60/604473/The_rcl_loop_scene/3'>RCL</scene> inserts into β-sheet A and forms an extra fourth β strand . The serpin conformational change is key to the mechanism of inhibition of target proteases.  
Structural studies on serpins revealed that inhibitory members of the family undergo an unusual conformational change, termed the Stressed to Relaxed (S to R) transition. During this structural transition the <scene name='60/604473/The_rcl_loop_scene/3'>RCL</scene> inserts into A β-sheet and forms an extra fourth β strand . The serpin conformational change is key to the mechanism of inhibition of target proteases. <scene name='60/604473/Rcl_insertion_into_beta_sheet/1'>Some amino-acids of RCL</scene> wich belong to a consensus sequence for inhibitory serpins are thought to permit efficient and rapid insertion of the RCL into the A β-sheet. The correspond-
<ref> James C Whisstocka, 2, Richard Skinnera, 2, Robin W Carrella, Arthur M Leska, Conformational changes in serpins: I. the native and cleaved conformations of α1-antitrypsin1, http://www.sciencedirect.com/science/article/pii/S0022283699935209 DOI:pii/S0022283699935209</ref>
<ref> James C Whisstocka, 2, Richard Skinnera, 2, Robin W Carrella, Arthur M Leska, Conformational changes in serpins: I. the native and cleaved conformations of α1-antitrypsin1, http://www.sciencedirect.com/science/article/pii/S0022283699935209 DOI:pii/S0022283699935209</ref>
When a protease attack a substrate, it catalyze peptide bond cleavage in a two-step process. First, the catalytic serine or cysteine performs a nucleophilic attack on the peptide bond of the substrate. This forms an new bond between the enzyme and the substrate. This covalent enzyme-substrate complex is called an acyl enzyme intermediate. Then, this bond is hydrolyzed and the C-terminus is released.  
When a protease attack a substrate, it catalyze peptide bond cleavage in a two-step process. First, the catalytic serine or cysteine performs a nucleophilic attack on the peptide bond of the substrate. This forms an new bond between the enzyme and the substrate. This covalent enzyme-substrate complex is called an acyl enzyme intermediate. Then, this bond is hydrolyzed and the C-terminus is released.  
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