4NZS

Crystal structure of beta-ketothiolase BktB B from Ralstonia eutropha H16

4NZS の概要

• エントリーDOI: 10.2210/pdb4nzs/pdb
• 分子名称: Beta-ketothiolase BktB (2 entities in total)
• 機能のキーワード: thiolase superfamily, transferase
• 由来する生物種: Ralstonia eutropha
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 83300.86

構造登録者

Kim, E.J.,Son, H.,Kim, S.,Kim, K.J. (登録日: 2013-12-12, 公開日: 2014-11-19, 最終更新日: 2023-11-08)

主引用文献

Kim, E.J.,Son, H.F.,Kim, S.,Ahn, J.W.,Kim, K.J.
Crystal structure and biochemical characterization of beta-keto thiolase B from polyhydroxyalkanoate-producing bacterium Ralstonia eutropha H16
Biochem.Biophys.Res.Commun., 444:365-369, 2014

PubMed Abstract: ReBktB is a β-keto thiolase from Ralstonia eutropha H16 that catalyzes condensation reactions between acetyl-CoA with acyl-CoA molecules that contains different numbers of carbon atoms, such as acetyl-CoA, propionyl-CoA, and butyryl-CoA, to produce valuable bioproducts, such as polyhydroxybutyrate, polyhydroxybutyrate-hydroxyvalerate, and hexanoate. We solved a crystal structure of ReBktB at 2.3Å, and the overall structure has a similar fold to that of type II biosynthetic thiolases, such as PhbA from Zoogloea ramigera (ZrPhbA). The superposition of this structure with that of ZrPhbA complexed with CoA revealed the residues that comprise the catalytic and substrate binding sites of ReBktB. The catalytic site of ReBktB contains three conserved residues, Cys90, His350, and Cys380, which may function as a covalent nucleophile, a general base, and second nucleophile, respectively. For substrate binding, ReBktB stabilized the ADP moiety of CoA in a distinct way compared to ZrPhbA with His219, Arg221, and Asp228 residues, whereas the stabilization of β-mercaptoethyamine and pantothenic acid moieties of CoA was quite similar between these two enzymes. Kinetic study of ReBktB revealed that K(m), V(max), and K(cat) values of 11.58 μM, 1.5 μmol/min, and 102.18 s(-1), respectively, and the catalytic and substrate binding sites of ReBktB were further confirmed by site-directed mutagenesis experiments.

PubMed: 24462871
DOI: 10.1016/j.bbrc.2014.01.055

実験手法

X-RAY DIFFRACTION (2.29 Å)