Catalyzes specifically the acetylation of the epsilon-amino group of a highly conserved lysine residue in acetyl-CoA synthetase (ACS) and of the universal stress protein (USP) MSMEG_4207. Acetylation results in the inactivation of ACS activity and could be important for mycobacteria to adjust to environmental changes. Allosterically regulated by cAMP. Homodimer. Disruption of this gene abolishes acetylation of USP.