View source for 4afr


==THE STRUCTURE OF METACASPASE 2 (C213A MUTANT) FROM T. BRUCEI==
<StructureSection load='4afr' size='340' side='right'caption='[[4afr]], [[Resolution|resolution]] 1.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4afr]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Trypanosoma_brucei_brucei Trypanosoma brucei brucei]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4AFR OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4AFR 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]] 1.6&#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=4afr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4afr OCA], [https://pdbe.org/4afr PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4afr RCSB], [https://www.ebi.ac.uk/pdbsum/4afr PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4afr ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/MCA2_TRYB2 MCA2_TRYB2] Cysteine protease that cleaves specifically after arginine or lysine residues.<ref>PMID:18005666</ref> <ref>PMID:23506317</ref> 
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== Publication Abstract from PubMed ==
Metacaspases are distantly related caspase-family cysteine peptidases implicated in programmed cell death in plants and lower eukaryotes. They differ significantly from caspases because they are calcium-activated, arginine-specific peptidases that do not require processing or dimerization for activity. To elucidate the basis of these differences and to determine the impact they might have on the control of cell death pathways in lower eukaryotes, the previously undescribed crystal structure of a metacaspase, an inactive mutant of metacaspase 2 (MCA2) from Trypanosoma brucei, has been determined to a resolution of 1.4 A. The structure comprises a core caspase fold, but with an unusual eight-stranded beta-sheet that stabilizes the protein as a monomer. Essential aspartic acid residues, in the predicted S1 binding pocket, delineate the arginine-specific substrate specificity. In addition, MCA2 possesses an unusual N terminus, which encircles the protein and traverses the catalytic dyad, with Y31 acting as a gatekeeper residue. The calcium-binding site is defined by samarium coordinated by four aspartic acid residues, whereas calcium binding itself induces an allosteric conformational change that could stabilize the active site in a fashion analogous to subunit processing in caspases. Collectively, these data give insights into the mechanistic basis of substrate specificity and mode of activation of MCA2 and provide a detailed framework for understanding the role of metacaspases in cell death pathways of lower eukaryotes.

Crystal structure of a Trypanosoma brucei metacaspase.,McLuskey K, Rudolf J, Proto WR, Isaacs NW, Coombs GH, Moss CX, Mottram JC Proc Natl Acad Sci U S A. 2012 May 8;109(19):7469-74. Epub 2012 Apr 23. PMID:22529389<ref>PMID:22529389</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 4afr" style="background-color:#fffaf0;"></div>

==See Also==
*[[Caspase 3D structures|Caspase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Trypanosoma brucei brucei]]
[[Category: Coombs GH]]
[[Category: Isaacs NW]]
[[Category: McLuskey K]]
[[Category: Moss CX]]
[[Category: Mottram JC]]
[[Category: Rudolf J]]