View source for 3req


==METHYLMALONYL-COA MUTASE, SUBSTRATE-FREE STATE (POOR QUALITY STRUCTURE)==
<StructureSection load='3req' size='340' side='right'caption='[[3req]], [[Resolution|resolution]] 2.70&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3req]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Propionibacterium_freudenreichii_subsp._shermanii Propionibacterium freudenreichii subsp. shermanii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3REQ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3REQ 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]] 2.7&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ADN:ADENOSINE'>ADN</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=3req FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3req OCA], [https://pdbe.org/3req PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3req RCSB], [https://www.ebi.ac.uk/pdbsum/3req PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3req ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/MUTB_PROFR MUTB_PROFR] Catalyzes the isomerization of succinyl-CoA to methylmalonyl-CoA during synthesis of propionate from tricarboxylic acid-cycle intermediates.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/re/3req_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=3req ConSurf].
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== Publication Abstract from PubMed ==
BACKGROUND: Methylmalonyl CoA mutase catalyses the interconversion of succinyl CoA and methylmalonyl CoA via a free radical mechanism. The enzyme belongs to a family of enzymes that catalyse intramolecular rearrangement reactions in which a group and a hydrogen atom on adjacent carbons are exchanged. These enzymes use the cofactor adenosylcobalamin (coenzyme B12) which breaks to form an adenosyl radical, thus initiating the reaction. Determination of the structure of substrate-free methylmalonyl CoA mutase was initiated to provide further insight into the mechanism of radical formation. RESULTS: We report here two structures of methylmalonyl CoA mutase from Propionibacterium shermanii. The first structure is of the enzyme in a nonproductive complex with CoA at 2.5 A resolution. This structure serves as a model for the substrate-free conformation of the enzyme, as it is very similar to the second much poorer 2.7 A resolution structure derived from a truly substrate-free crystal. The true substrate-free structure also shows the adenosyl group bound to the cobalt atom. Comparison of this structure with that of the previously reported complex of the enzyme with a substrate analogue shows that major conformational changes occur upon substrate binding. The substrate-binding site of the enzyme is located within a (beta alpha)8 TIM-barrel domain. In the absence of substrate, this TIM-barrel domain is split apart and the active site is accessible to solvent. When substrate binds, the barrel closes up with the substrate along its axis and the active site becomes completely buried. CONCLUSIONS: The closure of the active-site cavity upon substrate binding displaces the adenosyl group of the cofactor from the central cobalt atom into the active-site cavity. This triggers the formation of the free radical that initiates the rearrangement reaction. The TIM-barrel domain is substantially different from all others yet reported: in its unliganded form it is broken open, exposing the small hydrophilic sidechains which fill the centre. The typical barrel structure is only formed when substrate is bound.

Conformational changes on substrate binding to methylmalonyl CoA mutase and new insights into the free radical mechanism.,Mancia F, Evans PR Structure. 1998 Jun 15;6(6):711-20. PMID:9655823<ref>PMID:9655823</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Propionibacterium freudenreichii subsp. shermanii]]
[[Category: Evans PR]]
[[Category: Mancia F]]