Dear Editor,Although antimicrobial treatment of Staphylococcus aureus (S. aureus) infection is standard therapy for patients, mortality remains high as for the complications which include myocarditis. 1 Understanding the regulation of the proteome in the S. aureus bacterium may provide new insights in the treatment of this bacterial infection and also new basic knowledge of molecular signalling. Post-translational modification (PTM) of the lysine residue has significant consequences for functional and regulatory implications, including cytoskeleton complexes. 2 Specifically, N-lysine acetylation (Kac) and succinylation (Ksucc) prove to act as important PTMs for regulating various biological processes, including amino acid metabolism, protein translation and energy metabolism. 3,4 In this study, we systematically investigated lysine acetylation and succinylation sites in S. aureus using mass spectrometry (Supporting Information) and identified 1778 lysine acetylation sites from 794 proteins and 1651 lysine succinylation sites from 450 proteins. The finding, to our knowledge, is the largest number of acetylated and succinylated proteins to be discovered in S. aureus.Among the 794 lysine acetylated proteins in S. aureus, 48.1% and 6.3% have one or over five acetylated sites, respectively. We identified the top three proteins to be most poly-acetylated, which were oligopeptidase F (17 sites), phosphoglycerate kinase (11 sites) and elongation factor G (10 sites). For 450 lysine succinylated proteins, 33.3% were singly modified and 24.2% were poly-succinylated. The top three poly-succinylated proteins were bifunctional autolysin (23 sites), foldase protein PrsA (20 sites) and phosphoglycerate kinase (19 sites) (Figure 1A,B).To further characterize Kac and Ksucc sites, we examined the sequence motif around the identified peptides. Highly conserved motifs were found to be matched in the identified acetylated peptides (Figure 1C,F). These highly conserved motifs are consistent with previous reports, including eukaryotes, where Kac-tyrosine (Y) and Kachistidine (H) motifs were reported. 5,6 A heat map furtherThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.