View source for 4caa


==CLEAVED ANTICHYMOTRYPSIN T345R==
<StructureSection load='4caa' size='340' side='right'caption='[[4caa]], [[Resolution|resolution]] 2.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4caa]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=1ct3 1ct3]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4CAA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4CAA FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.9&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4caa FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4caa OCA], [https://pdbe.org/4caa PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4caa RCSB], [https://www.ebi.ac.uk/pdbsum/4caa PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4caa ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/AACT_HUMAN AACT_HUMAN] Although its physiological function is unclear, it can inhibit neutrophil cathepsin G and mast cell chymase, both of which can convert angiotensin-1 to the active angiotensin-2.<ref>PMID:2404007</ref> 
== 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/ca/4caa_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=4caa ConSurf].
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== Publication Abstract from PubMed ==
Expressed in a kinetically trapped folding state, a serpin couples the thermodynamic driving force of a massive beta-sheet rearrangement to the inhibition of a target protease. Hence, the serpin-protease interaction is the premier example of a "spring-loaded" protein-protein interaction. Amino acid substitutions in the hinge region of a serpin reactive loop can weaken the molecular spring, which converts the serpin from an inhibitor into a substrate. To probe the molecular basis of this conversion, we report the crystal structure of A349R antichymotrypsin in the reactive loop cleaved state at 2.1 A resolution. This amino acid substitution does not block the beta-sheet rearrangement despite the burial of R349 in the hydrophobic core of the cleaved serpin along with a salt-linked acetate ion. The inhibitory activity of this serpin variant is not obliterated; remarkably, its inhibitory properties are anion-dependent due to the creation of an anion-binding cavity in the cleaved serpin.

Engineering an anion-binding cavity in antichymotrypsin modulates the "spring-loaded" serpin-protease interaction.,Lukacs CM, Rubin H, Christianson DW Biochemistry. 1998 Mar 10;37(10):3297-304. PMID:9521649<ref>PMID:9521649</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 4caa" style="background-color:#fffaf0;"></div>

==See Also==
*[[Serpin 3D structures|Serpin 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Christianson DW]]
[[Category: Lukacs CM]]