Lysine Trimethylation in Planktonic and Pellicle Modes of Growth in Acinetobacter baumannii

Over the past 30 years, Acinetobacterbaumannii has been described as an important nosocomialpathogen due to frequentventilator-associated infections. Many biological processes of A. baumannii remain elusive, such as the formationof an air-liquid biofilm (pellicle). Several studies demonstratedthe importance of post-translational modifications (PTMs) in A. baumannii physiology. Here, we investigated K-trimethylationin A. baumannii ATCC 17978 in planktonicand pellicle modes using proteomic analysis. To identify the mosthigh-confidence K-trimethylated peptides, we compared different samplepreparation methods (i.e., strong cation exchange, antibody-capture)and processing software (i.e., different database search engines).We identified, for the first time, 84 K-trimethylated proteins, manyof which are involved in DNA and protein synthesis (HupB, RplK), transporters(Ata, AdeB), or lipid metabolism processes (FadB, FadD). In comparisonwith previous studies, several identical lysine residues were observedacetylated or trimethylated, indicating the presence of proteoformsand potential PTM cross-talks. This is the first large-scale proteomicstudy of trimethylation in A. baumannii and will be an important resource for the scientific community (availabilityin Pride repository under accession PXD035239).

Automated summary

Through proteomic analysis, we identified 84 K-trimethylated proteins in Acinetobacter baumannii for the first time, which is of great importance to the scientific community.