View source for 4lc1


==MeaB, A Bacterial Homolog of MMAA, Bound to GDP and crystallized in the presence of GDP and [AlF4]-==
<StructureSection load='4lc1' size='340' side='right'caption='[[4lc1]], [[Resolution|resolution]] 1.80&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4lc1]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Methylorubrum_extorquens_AM1 Methylorubrum extorquens AM1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4LC1 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4LC1 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]] 1.8&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GDP:GUANOSINE-5-DIPHOSPHATE'>GDP</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</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=4lc1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4lc1 OCA], [https://pdbe.org/4lc1 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4lc1 RCSB], [https://www.ebi.ac.uk/pdbsum/4lc1 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4lc1 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/C5AP93_METEA C5AP93_METEA] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
MeaB is an accessory GTPase protein involved in the assembly, protection and reactivation of 5'-deoxyadenosylcobalamin-dependent methyl malonyl-CoA mutase (MCM). Mutations in the human ortholog of MeaB result in methylmalonic aciduria, an inborn error of metabolism. G-proteins typically utilize conserved switch I and II motifs for signaling to effector proteins via conformational changes elicited by nucleotide-binding and hydrolysis. Our recent discovery that MeaB employs an unusual switch III region for bidirectional signaling with MCM raised questions about the roles of the switch I and II motifs in MeaB. In this study, we have addressed the functions of conserved switch II residues by performing alanine-scanning mutagenesis. Our results demonstrate that the GTPase activity of MeaB is auto-inhibited by switch II and that this loop is important for coupling nucleotide-sensitive conformational changes in switch III to elicit the multiple chaperone functions of MeaB. Furthermore, we report the structure of MeaB-GDP crystallized in the presence of AlFx- in order to form the putative transition state analog, GDP-AlF4-. The resulting crystal structure and its comparison to related G-proteins supports the conclusion that the catalytic site of MeaB is incomplete in the absence of the GTPase-activating protein, MCM, and therefore unable to stabilize the transition state analog. Favoring an inactive conformation in the absence of the client MCM protein might represent a strategy for suppressing the intrinsic GTPase activity of MeaB in which the switch II loop plays an important role.

Autoinhibition and signalling by the switch II motif in the G-protein chaperone of a radical B12 enzyme.,Lofgren M, Koutmos M, Banerjee R J Biol Chem. 2013 Aug 30. PMID:23996001<ref>PMID:23996001</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4lc1" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Methylorubrum extorquens AM1]]
[[Category: Banerjee R]]
[[Category: Koutmos M]]
[[Category: Lofgren M]]
[[Category: Padovani D]]