Abstract
Post-translational modifications of proteins enable swift physiological adaptation of cells to altered growth conditions and stress. Aside from protein phosphorylation, acetylation on ε-amino groups of lysine residues (N-ε-lysine acetylation) represents another important post-translational modification of proteins.
For many bacterial pathogens, including the whooping cough agent Bordetella pertussis, the role and extent of protein acetylation remains to be defined. We expressed in E. coli the BP0960 and BP3063 genes encoding two putative deacetylases of B. pertussis and show that BP0960 encodes a lysine deacetylase enzyme, named Bkd1, that regulates acetylation of a range of B. pertussis proteins.
Comparison of the proteome and acetylome of a Δbkd1 mutant with the proteome and acetylome of wild-type B. pertussis (PRIDE ID. PXD016384) revealed that acetylation on lysine residues may modulate activities or stabilities of proteins involved in bacterial metabolism and histone-like proteins.
However, increased acetylation of the BvgA response regulator protein of the B. pertussis master virulence-regulating BvgAS two-component system affected neither the total levels of produced BvgA, nor its phosphorylation status. Indeed, the Δbkd1 mutant was not impaired in production of key virulence factors and its survival within human macrophages in vitro was not affected.
The Δbkd1 mutant exhibited an increased growth rate under carbon source-limiting conditions and its virulence in the in vivo mouse lung infection model was somewhat affected. These results indicate that the lysine deacetylase Bkd1 and the N-ε-lysine acetylation primarily modulate the general metabolism rather than virulence of B. pertussis.