Systematic analysis of the lysine acetylome of the pathogenic bacterium Spiroplasma eriocheiris reveals acetylated proteins related to metabolism and helical structure.

UNLABELLED: Post-translational modifications such as acetylation are an essential regulatory mechanism of protein function. Spiroplasma eriocheiris, with no cell wall and a helical structure, is a novel pathogen of freshwater crustacean. There is no other evidence of acylation (such as succinylation and propionylation) except acetylation genes in S. eriocheiris concise genome. So the acetylation may play an important role in S. eriocheiris. Here, we conducted the first lysine acetylome in S. eriocheiris. We identified 2567 lysine acetylation sites in 555 proteins, which account for 44.69% of the total proteins in this bacterium. To date, this is the highest ratio of acetylated proteins that have been identified in bacteria. Fifteen types of acetylated peptide sequence motifs were revealed from the acetylome. Forty-five lysine-acetylated proteins showed homology with acetylated proteins previously identified from Escherichia coli, Vibrio parahemolyticus and Mycobacterium tuberculosis. Notably, most proteins in glycolysis and all proteins in the arginine deiminase system were acetylated. Meanwhile, the cell skeleton proteins (Fibril and Mrebs) were all acetylated the observed acetylation also played an important role in cell skeleton formation. The results imply previously unreported hidden layers of post-translational regulation in lysine acetylation that define the functional state of Spiroplasma. BIOLOGICAL SIGNIFICANCE: This is the first time to analyze PTM of Spiroplasma. This is the highest ratio of acetylated proteins that have been identified in bacteria. S. eriocheiris lysine acetylome reveals acetylated proteins related to metabolism and helical structure. These data provide an important resource to elucidate the role of acetylation in Spiroplasma cellular physiology.