Acetylation of acetyl-CoA synthetase from Mycobacterium tuberculosis leads to specific inactivation of the adenylation reaction

Tahel Noy, Hua Xu, John S. Blanchard

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Acetyl-CoA synthetase (ACS) catalyzes the formation of AcCoA from acetate, ATP and Coenzyme A, allowing the organism to grow on acetate as the sole carbon source. ACS was the first enzyme in Mycobacterium tuberculosis shown to be regulated by posttranslational acetylation by the cAMP-dependent protein acetyltransferase. This modification results in the inactivation of the enzyme and can be reversed in the presence of NAD+ and a mycobacterial sirtuin-like deacetylase. In this study we characterize the kinetic mechanism of MtACS, where the overall reaction can be divided into two half-reactions: the acetyl-adenylate forming reaction and the thiol-ligation reaction. We also provide evidence for the existence of the acetyl-adenylate intermediate via 31P NMR spectroscopy. Furthermore, we dissect the regulatory role of K617 acetylation and show that acetylation inhibits only the first, adenylation half-reaction while leaving the second half reaction unchanged. Finally, we demonstrate that the chemical mechanism of the enzyme relies on a conformational change which is controlled by the protonation state of aspartate 525. Together with our earlier results, this suggests a degree of regulation of enzyme activity that is appropriate for the role of the enzyme in central carbon metabolism.

Original languageEnglish (US)
Pages (from-to)42-49
Number of pages8
JournalArchives of Biochemistry and Biophysics
Volume550-551
DOIs
StatePublished - May 15 2014

Keywords

  • Central carbon metabolism
  • Enzyme kinetics
  • Enzyme regulation
  • Tuberculosis

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

Fingerprint Dive into the research topics of 'Acetylation of acetyl-CoA synthetase from Mycobacterium tuberculosis leads to specific inactivation of the adenylation reaction'. Together they form a unique fingerprint.

Cite this