<i>Aeromonas hydrophila</i> CobQ is a new type of NAD⁺- and Zn²⁺-independent protein lysine deacetylase.

Abstract

Protein N^Ɛ-lysine acetylation (Kac) modifications play crucial roles in diverse physiological and pathological functions in cells. In prokaryotic cells, there are only two types of lysine deacetylases (KDACs) that are Zn²⁺- or NAD⁺-dependent. In this study, we reported a protein, AhCobQ, in <i>Aeromonas hydrophila</i> ATCC 7966 that presents NAD⁺- and Zn²⁺-independent KDAC activity. Furthermore, its KDAC activity is located in an unidentified domain (from 195 to 245 aa). Interestingly, AhCobQ has no homology with current known KDACs, and no homologous protein was found in eukaryotic cells. A protein substrate analysis showed that AhCobQ has specific protein substrates in common with other known KDACs, indicating that these KDACs can dynamically co-regulate the states of Kac proteins. Microbiological methods employed in this study affirmed AhCobQ's positive regulation of isocitrate dehydrogenase (ICD) enzymatic activity at the K388 site, implicating AhCobQ in the modulation of bacterial enzymatic activities. In summary, our findings present compelling evidence that AhCobQ represents a distinctive type of KDAC with significant roles in bacterial biological functions.