Site-specific acylation of a bacterial virulence regulator attenuates infection

Nat Chem Biol. 2020 Jan;16(1):95-103. doi: 10.1038/s41589-019-0392-5. Epub 2019 Nov 18.


Microbiota generates millimolar concentrations of short-chain fatty acids (SCFAs) that can modulate host metabolism, immunity and susceptibility to infection. Butyrate in particular can function as a carbon source and anti-inflammatory metabolite, but the mechanism by which it inhibits pathogen virulence has been elusive. Using chemical proteomics, we found that several virulence factors encoded by Salmonella pathogenicity island-1 (SPI-1) are acylated by SCFAs. Notably, a transcriptional regulator of SPI-1, HilA, was acylated on several key lysine residues. Subsequent incorporation of stable butyryl-lysine analogs using CRISPR-Cas9 gene editing and unnatural amino acid mutagenesis revealed that site-specific modification of HilA impacts its genomic occupancy, expression of SPI-1 genes and attenuates Salmonella enterica serovar Typhimurium invasion of epithelial cells, as well as dissemination in vivo. Moreover, a multiple-site HilA lysine acylation mutant strain of S. Typhimurium was resistant to butyrate inhibition ex vivo and microbiota attenuation in vivo. Our results suggest that prominent microbiota-derived metabolites may directly acylate virulence factors to inhibit microbial pathogenesis in vivo.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arginine / chemistry
  • Bacterial Proteins / metabolism
  • Binding Sites
  • Butyrates / chemistry
  • CRISPR-Cas Systems
  • Fatty Acids / metabolism*
  • Gene Expression Regulation, Bacterial*
  • Genome, Bacterial
  • Genomic Islands*
  • Genomics
  • Lysine / chemistry
  • Mice
  • Mice, Inbred C57BL
  • Mutagenesis
  • Mutation
  • Proteomics / methods
  • Salmonella typhimurium / metabolism*
  • Salmonella typhimurium / pathogenicity
  • Trans-Activators / metabolism
  • Virulence Factors / metabolism
  • Virulence*


  • Bacterial Proteins
  • Butyrates
  • Fatty Acids
  • Trans-Activators
  • Virulence Factors
  • Arginine
  • Lysine