View source for 3tnx


==Structure of the precursor of a thermostable variant of papain at 2.6 Angstroem resolution==
<StructureSection load='3tnx' size='340' side='right'caption='[[3tnx]], [[Resolution|resolution]] 2.62&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3tnx]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Carica_papaya Carica papaya]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3TNX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3TNX 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]] 2.62&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene></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=3tnx FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3tnx OCA], [https://pdbe.org/3tnx PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3tnx RCSB], [https://www.ebi.ac.uk/pdbsum/3tnx PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3tnx ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/PAPA1_CARPA PAPA1_CARPA] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Papain is the archetype of a broad class of cysteine proteases (clan C1A) that contain a pro-peptide in the zymogen form which is required for correct folding and spatio-temporal regulation of proteolytic activity in the initial stages after expression. This study reports the X-ray structure of the zymogen of a thermostable mutant of papain at 2.6 A resolution. The overall structure, in particular that of the mature part of the protease, is similar to those of other members of the family. The structure provides an explanation for the molecular basis of the maintenance of latency of the proteolytic activity of the zymogen by its pro-segment at neutral pH. The structural analysis, together with biochemical and biophysical studies, demonstrated that the pro-segment of the zymogen undergoes a rearrangement in the form of a structural loosening at acidic pH which triggers the proteolytic activation cascade. This study further explains the bimolecular stepwise autocatalytic activation mechanism by limited proteolysis of the zymogen of papain at the molecular level. The possible factors responsible for the higher thermal stability of the papain mutant have also been analyzed.

The structure of a thermostable mutant of pro-papain reveals its activation mechanism.,Roy S, Choudhury D, Aich P, Dattagupta JK, Biswas S Acta Crystallogr D Biol Crystallogr. 2012 Dec;68(Pt 12):1591-603. doi:, 10.1107/S0907444912038607. Epub 2012 Nov 9. PMID:23151624<ref>PMID:23151624</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3tnx" style="background-color:#fffaf0;"></div>

==See Also==
*[[Papain|Papain]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Carica papaya]]
[[Category: Large Structures]]
[[Category: Biswas S]]
[[Category: Choudhury D]]
[[Category: Dattagupta JK]]
[[Category: Roy S]]