View source for 4xc8


==Isobutyryl-CoA mutase fused with bound butyryl-CoA, GDP, and Mg and without cobalamin (apo-IcmF/GDP)==
<StructureSection load='4xc8' size='340' side='right'caption='[[4xc8]], [[Resolution|resolution]] 3.25&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4xc8]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Cupriavidus_metallidurans_CH34 Cupriavidus metallidurans CH34]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4XC8 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4XC8 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]] 3.25&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BCO:BUTYRYL+COENZYME+A'>BCO</scene>, <scene name='pdbligand=GDP:GUANOSINE-5-DIPHOSPHATE'>GDP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</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=4xc8 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4xc8 OCA], [https://pdbe.org/4xc8 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4xc8 RCSB], [https://www.ebi.ac.uk/pdbsum/4xc8 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4xc8 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/ICMF_CUPMC ICMF_CUPMC] Catalyzes the reversible interconversion of isobutyryl-CoA and n-butyryl-CoA, and to a much lesser extent, of pivalyl-CoA and isovaleryl-CoA, using radical chemistry (PubMed:22167181). Also exhibits GTPase activity, associated with its G-protein domain (MeaI) that functions as a chaperone that assists cofactor delivery and proper holo-enzyme assembly (PubMed:22167181, PubMed:25675500). The G-domain of IcmF has also a role in its cofactor repair (PubMed:28130442). Does not display ATPase activity.<ref>PMID:22167181</ref> <ref>PMID:25675500</ref> <ref>PMID:28130442</ref> 
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== Publication Abstract from PubMed ==
G-protein metallochaperones ensure fidelity during cofactor assembly for a variety of metalloproteins, including adenosylcobalamin (AdoCbl)-dependent methylmalonyl-CoA mutase and hydrogenase, and thus have both medical and biofuel development applications. Here, we present crystal structures of IcmF, a natural fusion protein of AdoCbl-dependent isobutyryl-CoA mutase and its corresponding G-protein chaperone, which reveal the molecular architecture of a G-protein metallochaperone in complex with its target protein. These structures show that conserved G-protein elements become ordered upon target protein association, creating the molecular pathways that both sense and report on the cofactor loading state. Structures determined of both apo- and holo-forms of IcmF depict both open and closed enzyme states, in which the cofactor-binding domain is alternatively positioned for cofactor loading and for catalysis. Notably, the G protein moves as a unit with the cofactor-binding domain, providing a visualization of how a chaperone assists in the sequestering of a precious cofactor inside an enzyme active site.

Visualization of a radical B12 enzyme with its G-protein chaperone.,Jost M, Cracan V, Hubbard PA, Banerjee R, Drennan CL Proc Natl Acad Sci U S A. 2015 Feb 24;112(8):2419-24. doi:, 10.1073/pnas.1419582112. Epub 2015 Feb 9. PMID:25675500<ref>PMID:25675500</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4xc8" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Cupriavidus metallidurans CH34]]
[[Category: Large Structures]]
[[Category: Drennan CL]]
[[Category: Jost M]]