View source for 1cew


==THE 2.0 ANGSTROMS X-RAY CRYSTAL STRUCTURE OF CHICKEN EGG WHITE CYSTATIN AND ITS POSSIBLE MODE OF INTERACTION WITH CYSTEINE PROTEINASES==
<StructureSection load='1cew' size='340' side='right'caption='[[1cew]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1cew]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Chick Chick]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CEW OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1CEW FirstGlance]. <br>
</td></tr><tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1cew FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1cew OCA], [http://pdbe.org/1cew PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1cew RCSB], [http://www.ebi.ac.uk/pdbsum/1cew PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1cew ProSAT]</span></td></tr>
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== Function ==
[[http://www.uniprot.org/uniprot/CYT_CHICK CYT_CHICK]] This protein binds tightly to and inhibits a variety of thiol proteases including ficin, papain, and cathepsins B, C, H, and L. Although isolated from egg white, it is also present in serum. 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/ce/1cew_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1cew ConSurf].
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== Publication Abstract from PubMed ==
The crystal structure of chicken egg white cystatin has been solved by X-ray diffraction methods using the multiple isomorphous replacement technique. Its structure has been refined to a crystallographic R value of 0.19 using X-ray data between 6 and 2.0A. The molecule consists mainly of a straight five-turn alpha-helix, a five-stranded antiparallel beta-pleated sheet which is twisted and wrapped around the alpha-helix and an appending segment of partially alpha-helical geometry. The 'highly conserved' region from Gln53I to Gly57I implicated with binding to cysteine proteinases folds into a tight beta-hairpin loop which on opposite sides is flanked by the amino-terminal segment and by a second hairpin loop made up of the similarly conserved segment Pro103I - Trp104I. These loops and the amino-terminal Gly9I - Ala10I form a wedge-shaped 'edge' which is quite complementary to the 'active site cleft' of papain. Docking experiments suggest a unique model for the interaction of cystatin and papain: according to it both hairpin loops of cystatin make major binding interactions with the highly conserved residues Gly23, Gln19, Trp177 and Ala136 of papain in the neighbourhood of the reactive site Cys25; the amino-terminal segment Gly9I - Ala10I of bound cystatin is directed towards the substrate subsite S2, but in an inappropriate conformation and too far away to be attacked by the reactive site Cys25. As a consequence, the mechanism of the interaction between cysteine proteinases and their cystatin-like inhibitors seems to be fundamentally different from the 'standard mechanism' defined for serine proteinases and most of their protein inhibitors.

The 2.0 A X-ray crystal structure of chicken egg white cystatin and its possible mode of interaction with cysteine proteinases.,Bode W, Engh R, Musil D, Thiele U, Huber R, Karshikov A, Brzin J, Kos J, Turk V EMBO J. 1988 Aug;7(8):2593-9. PMID:3191914<ref>PMID:3191914</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
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</StructureSection>
[[Category: Chick]]
[[Category: Large Structures]]
[[Category: Bode, W]]
[[Category: Huber, R]]
[[Category: Musil, D]]