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==Crystal structure of 2-Hydroxyisobutyryl-CoA Ligase (HCL) in the postadenylation state in complex with R3-HIB-AMP==
<StructureSection load='6hdx' size='340' side='right'caption='[[6hdx]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6hdx]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6HDX OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6HDX FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=8LH:[[(2~{R},3~{S},4~{R},5~{R})-5-(6-aminopurin-9-yl)-3,4-bis(oxidanyl)oxolan-2-yl]methoxy-oxidanyl-phosphoryl]+(2~{R})-2-methyl-3-oxidanyl-propanoate'>8LH</scene>, <scene name='pdbligand=HIU:(2R)-3-HYDROXY-2-METHYLPROPANOIC+ACID'>HIU</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6hdx FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6hdx OCA], [http://pdbe.org/6hdx PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6hdx RCSB], [http://www.ebi.ac.uk/pdbsum/6hdx PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6hdx ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
2-Hydroxyisobutyric acid (2-HIBA) is a biomarker of adiposity and associated metabolic diseases such as diabetes mellitus. It is also formed in the bacterial degradation pathway of the fuel oxygenate methyl tert-butyl ether (MTBE), requiring thioesterification with CoA prior to isomerization to 3-hydroxybutyryl-CoA by B12-dependent acyl-CoA mutases. Here, we identify the adenylating enzymes superfamily member 2-HIBA-CoA ligase (HCL) in the MTBE-degrading bacterium Aquincola tertiaricarbonis L108 by knockout experiments. To characterize this central enzyme of 2-HIBA metabolism, ligase activity kinetics of purified HCL and its X-ray crystal structures were studied. We analyzed the enzyme in three states, which differ in the orientation of the two enzyme domains. A 154 degrees rotation of the C-terminal domain accompanies the switch from the adenylate- into the thioester-forming state. Furthermore, a third conformation was obtained, which differs by 50 degrees and 130 degrees from the adenylation and thioesterification states, respectively. Phylogenetic and structural analysis reveals that HCL defines a new subgroup within phenylacetate-CoA ligases (PCLs) thus far described to exclusively accept aromatic acyl substrates. In contrast, kinetic characterization clearly demonstrated that HCL catalyzes CoA activation of several aliphatic short-chain carboxylic acids, preferentially 2-HIBA. Compared to the classical PCL representatives PaaK1 and PaaK2 of Burkholderia cenocepacia J2315, the acyl binding pocket of HCL is significantly smaller and more polar, due to unique active-site residues Y164 and S239 forming H-bonds with the OH-group of the acyl substrate moiety. Furthermore, HCL and PaaK topologies illustrate the evolutionary steps leading from a homodimeric to the fused monomeric core fold found in other ligases.

Structures of 2-Hydroxyisobutyric Acid-CoA Ligase Reveal Determinants of Substrate Specificity and Describe a Multi-Conformational Catalytic Cycle.,Zahn M, Kurteva-Yaneva N, Schuster J, Krug U, Georgi T, Muller RH, Rohwerder T, Strater N J Mol Biol. 2019 Jul 12;431(15):2747-2761. doi: 10.1016/j.jmb.2019.05.027. Epub, 2019 May 28. PMID:31145912<ref>PMID:31145912</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 6hdx" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Rohwerder, T]]
[[Category: Strater, N]]
[[Category: Zahn, M]]
[[Category: 2-hydroxyisobutyrate coa]]
[[Category: Ligase]]