View source for 4w61


==Crystal structure of beta-ketoacyl thiolase B (BktB) from Ralstonia eutropha==
<StructureSection load='4w61' size='340' side='right'caption='[[4w61]], [[Resolution|resolution]] 2.01&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4w61]] is a 16 chain structure with sequence from [https://en.wikipedia.org/wiki/Cupriavidus_necator_H16 Cupriavidus necator H16]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4W61 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4W61 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]] 2.01&#8491;</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=4w61 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4w61 OCA], [https://pdbe.org/4w61 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4w61 RCSB], [https://www.ebi.ac.uk/pdbsum/4w61 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4w61 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/BKTB_CUPNH BKTB_CUPNH] Required for efficient production of poly(beta-hydroxybutyrate-co-beta-hydroxyvalerate) (PHBV). Catalyzes the condensation of acetyl-CoA and propionyl-CoA to form beta-ketovaleryl-CoA, and the condensation of two acetyl-CoA molecules to form acetoacetyl-CoA.<ref>PMID:9555876</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Thiolases catalyze the formation of carbon-carbon bonds in diverse biosynthetic pathways. The promiscuous beta-ketoacyl thiolase B of Ralstonia eutropha (ReBktB) has been utilized in the in vivo conversion of Coenzyme A (CoA)-linked precursors such as acetyl-CoA and glycolyl-CoA into beta-hydroxy acids, including the pharmaceutically-important 3,4-dihydroxybutyric acid. Such thiolases could serve as powerful carbon-carbon bond-forming biocatalysts in vitro if handles less costly than CoA were employable. Here, thiolase activity is demonstrated toward substrates linked to the readily-available CoA mimic, N-acetylcysteamine (NAC). ReBktB was observed to catalyze the retro-Claisen condensation of several beta-ketoacyl-S-NAC substrates, with a preference for 3-oxopentanoyl-S-NAC over 3-oxobutanoyl-, 3-oxohexanoyl-, and 3-oxoheptanoyl-S-NAC. A 2.0 A-resolution crystal structure, in which the asymmetric unit consists of four ReBktB tetramers, provides insight into acyl group specificity and how it may be engineered. By replacing an active site methionine with an alanine, a mutant possessing significant activity towards alpha-methyl substituted, NAC-linked substrates was engineered. The ability of ReBktB and its engineered mutants to utilize NAC-linked substrates will facilitate the in vitro biocatalytic synthesis of diketide chiral building blocks from feedstock molecules such as acetate and propionate.

Coenzyme A-free activity, crystal structure, and rational engineering of a promiscuous beta-ketoacyl thiolase from Ralstonia eutropha.,Fage CD, Meinke JL, Keatinge-Clay AT J Mol Catal B Enzym. 2015 Nov 1;121:113-121. doi: 10.1016/j.molcatb.2015.08.007. PMID:26494979<ref>PMID:26494979</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 4w61" style="background-color:#fffaf0;"></div>

==See Also==
*[[Thiolase 3D structures|Thiolase 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Cupriavidus necator H16]]
[[Category: Large Structures]]
[[Category: Fage CD]]
[[Category: Keatinge-Clay AT]]