View source for 5ibc


==Caspase 3 V266I==
<StructureSection load='5ibc' size='340' side='right'caption='[[5ibc]], [[Resolution|resolution]] 1.66&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5ibc]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [https://en.wikipedia.org/wiki/Unidentified Unidentified]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5IBC OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5IBC 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]] 1.66&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=0QE:CHLOROMETHANE'>0QE</scene>, <scene name='pdbligand=ACE:ACETYL+GROUP'>ACE</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</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=5ibc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5ibc OCA], [https://pdbe.org/5ibc PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5ibc RCSB], [https://www.ebi.ac.uk/pdbsum/5ibc PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5ibc ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CASP3_HUMAN CASP3_HUMAN] Involved in the activation cascade of caspases responsible for apoptosis execution. At the onset of apoptosis it proteolytically cleaves poly(ADP-ribose) polymerase (PARP) at a '216-Asp-|-Gly-217' bond. Cleaves and activates sterol regulatory element binding proteins (SREBPs) between the basic helix-loop-helix leucine zipper domain and the membrane attachment domain. Cleaves and activates caspase-6, -7 and -9. Involved in the cleavage of huntingtin. Triggers cell adhesion in sympathetic neurons through RET cleavage.<ref>PMID:7596430</ref> <ref>PMID:21357690</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The native ensemble of caspases is described globally by a complex energy landscape where the binding of substrate selects for the active conformation, whereas targeting an allosteric site in the dimer interface selects an inactive conformation that contains disordered active-site loops. Mutations and posttranslational modifications stabilize high-energy inactive conformations, with mostly formed, but distorted, active sites. To examine the interconversion of active and inactive states in the ensemble, we used detection of related solvent positions to analyze 4,995 waters in 15 high-resolution (&lt;2.0 A) structures of wild-type caspase-3, resulting in 450 clusters with the most highly conserved set containing 145 water molecules. The data show that regions of the protein that contact the conserved waters also correspond to sites of posttranslational modifications, suggesting that the conserved waters are an integral part of allosteric mechanisms. To test this hypothesis, we created a library of 19 caspase-3 variants through saturation mutagenesis in a single position of the allosteric site of the dimer interface, and we show that the enzyme activity varies by more than four orders of magnitude. Altogether, our database consists of 37 high-resolution structures of caspase-3 variants, and we demonstrate that the decrease in activity correlates with a loss of conserved water molecules. The data show that the activity of caspase-3 can be fine-tuned through globally desolvating the active conformation within the native ensemble, providing a mechanism for cells to repartition the ensemble and thus fine-tune activity through conformational selection.

Tunable allosteric library of caspase-3 identifies coupling between conserved water molecules and conformational selection.,Maciag JJ, Mackenzie SH, Tucker MB, Schipper JL, Swartz P, Clark AC Proc Natl Acad Sci U S A. 2016 Oct 11;113(41):E6080-E6088. Epub 2016 Sep 28. PMID:27681633<ref>PMID:27681633</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5ibc" style="background-color:#fffaf0;"></div>

==See Also==
*[[Caspase 3D structures|Caspase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Unidentified]]
[[Category: Clark AC]]
[[Category: Maciag JJ]]
[[Category: Mackenzie SH]]
[[Category: Schipper JL]]
[[Category: Swartz PD]]
[[Category: Tucker MB]]