Crystal structure of an acetyl-CoA acetyltransferase from PHB producing bacterium Bacillus cereus ATCC 14579

Biochem Biophys Res Commun. 2020 Dec 10;533(3):442-448. doi: 10.1016/j.bbrc.2020.09.048. Epub 2020 Sep 22.

Abstract

Bacillus cereus ATCC 14579 is a known polyhydroxybutyrate (PHB)-producing microorganism that possesses genes associated with PHB synthesis such as PhaA, PhaB, and PHA synthases. PhaA (i.e., thiolase) is the first enzyme in the PHA biosynthetic pathway, which catalyze the condensation of two acetyl-CoA molecules to acetoacetyl-CoA. Our study elucidated the crystal structure of PhaA in Bacillus cereus ATCC 14579 (BcTHL) in its apo- and CoA-bound forms. BcTHL adopts a type II biosynthetic thiolase structure by forming a tetramer. The crystal structure of CoA-complexed BcTHL revealed that the substrate binding site of BcTHL is constituted by different residues compared with other known thiolases. Our study also revealed that Arg221, a residue involved in ADP binding, undergoes a positional conformational change upon the binding of the CoA molecule.

Keywords: Acetyl-CoA acetyltransferase; Bacillus cereus; Polyhydroxybutyrate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetyl-CoA C-Acetyltransferase / chemistry*
  • Bacillus cereus / enzymology*
  • Bacterial Proteins / chemistry*
  • Catalytic Domain
  • Coenzyme A / chemistry
  • Crystallography, X-Ray
  • Hydroxybutyrates / metabolism
  • Models, Molecular

Substances

  • Bacterial Proteins
  • Hydroxybutyrates
  • Acetyl-CoA C-Acetyltransferase
  • Coenzyme A