View source for 1olx


==Roles of His291-alpha and His146-beta' in the reductive acylation reaction catalyzed by human branched-chain alpha-ketoacid dehydrogenase==
<StructureSection load='1olx' size='340' side='right'caption='[[1olx]], [[Resolution|resolution]] 2.25&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1olx]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1OLX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1OLX 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]] 2.25&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</scene>, <scene name='pdbligand=MN:MANGANESE+(II)+ION'>MN</scene>, <scene name='pdbligand=TPP:THIAMINE+DIPHOSPHATE'>TPP</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=1olx FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1olx OCA], [https://pdbe.org/1olx PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1olx RCSB], [https://www.ebi.ac.uk/pdbsum/1olx PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1olx ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/ODBA_HUMAN ODBA_HUMAN] Defects in BCKDHA are a cause of maple syrup urine disease type IA (MSUD1A) [MIM:[https://omim.org/entry/248600 248600]. MSUD is an autosomal recessive disorder characterized by mental and physical retardation, feeding problems, and a maple syrup odor to the urine.<ref>PMID:2060625</ref> <ref>PMID:8037208</ref> <ref>PMID:2703538</ref> <ref>PMID:2241958</ref> <ref>PMID:1867199</ref> <ref>PMID:1885764</ref> <ref>PMID:8161368</ref> <ref>PMID:7883996</ref> 
== Function ==
[https://www.uniprot.org/uniprot/ODBA_HUMAN ODBA_HUMAN] The branched-chain alpha-keto dehydrogenase complex catalyzes the overall conversion of alpha-keto acids to acyl-CoA and CO(2). It contains multiple copies of three enzymatic components: branched-chain alpha-keto acid decarboxylase (E1), lipoamide acyltransferase (E2) and lipoamide dehydrogenase (E3).
== 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/ol/1olx_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=1olx ConSurf].
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== Publication Abstract from PubMed ==
We report here that alterations of either His291-alpha or His146-beta' in the active site of human branched-chain alpha-ketoacid dehydrogenase (E1b) impede both the decarboxylation and the reductive acylation reactions catalyzed by E1b as well as the binding of cofactor thiamin diphosphate (ThDP). In a refined human E1b active-site structure, His291-alpha, which aligns with His407 in Escherichia coli pyruvate dehydrogenase and His263 in yeast transketolase, is on a largely ordered phosphorylation loop. The imidazole ring of His291-alpha in E1b coordinates to the terminal phosphate oxygen atoms of bound ThDP. The N3 atom of wild-type His146-beta', which can be protonated, binds a water molecule and points toward the aminopyrimidine ring of ThDP. Remarkably, the H291A-alpha mutation results in a complete order-to-disorder transition of the loop region, which precludes the binding of the substrate lipoyl-bearing domain to E1b. The H146A-beta' mutation, on the other hand, does not alter the loop structure, but nullifies the reductive acylation activity of E1b. Our results suggest that: 1) His291-alpha plays a structural rather than a catalytic role in the binding of cofactor ThDP and the lipoyl-bearing domain to E1b, and 2) His146-beta' is an essential catalytic residue, probably functioning as a proton donor in the reductive acylation of lipoamide on the lipoyl-bearing domain.

Roles of His291-alpha and His146-beta' in the reductive acylation reaction catalyzed by human branched-chain alpha-ketoacid dehydrogenase: refined phosphorylation loop structure in the active site.,Wynn RM, Machius M, Chuang JL, Li J, Tomchick DR, Chuang DT J Biol Chem. 2003 Oct 31;278(44):43402-10. Epub 2003 Aug 5. PMID:12902323<ref>PMID:12902323</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 1olx" style="background-color:#fffaf0;"></div>

==See Also==
*[[2-oxoisovalerate dehydrogenase 3D structures|2-oxoisovalerate dehydrogenase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Chuang DT]]
[[Category: Chuang JL]]
[[Category: Li J]]
[[Category: Machius M]]
[[Category: Tomchick DR]]
[[Category: Wynn RM]]