YcgC represents a new protein deacetylase family in prokaryotes

Reversible lysine acetylation is one of the most important protein posttranslational modifications that plays essential roles in both prokaryotes and eukaryotes. However, only a few lysine deacetylases (KDACs) have been identified in prokaryotes, perhaps in part due to their limited sequence homology. Herein, we developed a ‘clip-chip’ strategy to enable unbiased, activity-based discovery of novel KDACs in the Escherichia coli proteome. In-depth biochemical characterization confirmed that YcgC is a serine hydrolase involving Ser200 as the catalytic nucleophile for lysine deacetylation and does not use NAD+ or Zn2+ like other established KDACs. Further, in vivo characterization demonstrated that YcgC regulates transcription by catalyzing deacetylation of Lys52 and Lys62 of a transcriptional repressor RutR. Importantly, YcgC targets a distinct set of substrates from the only known E. coli KDAC CobB. Analysis of YcgC’s bacterial homologs confirmed that they also exhibit KDAC activity. YcgC thus represents a novel family of prokaryotic KDACs. DOI: http://dx.doi.org/10.7554/eLife.05322.001
eLife digest After proteins have been made, they can be modified in several ways. For example, chemical tags called acetyl groups may be added to (and later removed from) the protein to regulate cell activities such as aging and metabolism. Enzymes are proteins that help catalyze the reactions that add or remove the acetyl tags on certain “substrate” proteins. In the bacteria species Escherichia coli, many enzymes that help to add acetyl groups to proteins have been discovered. However, only a single E. coli “deacetylase” enzyme that removes the acetyl group has been identified. Now, Tu, Guo, Chen et al. have devised a technique to identify new deacetylases, called the “clip-chip” approach. In this method, thousands of proteins that are potential deacetylases are arrayed on a glass slide, and substrate proteins are immobilized on another slide. The two slides are then clipped together face-to-face, allowing the potential enzymes to transfer to the substrate slide and interact with the substrates. Using this approach, Tu, Guo, Chen et al. identified a protein called YcgC as a deacetylase in bacteria. Further characterization experiments revealed that YcgC works in a different way to other known deacetylases, and that it targets different substrates to the previously known E. coli deacetylase. Tu, Guo, Chen et al. found that the equivalents of YcgC in other bacteria species are also deacetylases; these enzymes therefore represent a new deacetylase family. In the future, the clip-chip approach could be used to discover new members of other enzyme families. DOI: http://dx.doi.org/10.7554/eLife.05322.002