Protein Lysine Crotonylation Analysis Reveals an Important Role in the Regulation of Aeromonas hydrophila Maltose Transport

Protein lysine crotonylation (Kcr) has been reported
to play a
role in the regulation of prokaryotic cell metabolism. However, its
distribution and functional significance remain largely unexplored.
In this study, a global proteomic landscape of Kcr in Aeromonas hydrophila was mapped, identifying 4424
Kcr sites on 1248 proteins using LC-MS/MS. Gene ontology analysis
revealed that Kcr-modified proteins are primarily enriched in cellular
and primary metabolic processes, stress responses, macromolecule biosynthesis,
and transmembrane transport. Moreover, Kcr proteins are involved in
diverse metabolic pathways, such as the pentose phosphate pathway,
TCA cycle, and methane metabolism. Functional validation assays revealed
that the maltodextrin-binding protein (MalE) at the K57 site, as well
as the maltose/maltodextrin import ATP-binding protein (MalK) at the
K11 and K181 sites, positively regulated maltose transport, whereas
the K223 site on MalE had a negative regulatory effect. Bioinformatics
analysis further demonstrated that the different Kcr status at the
K11 site of MalK may positively regulate the cavity volume within
the MalFGK2 complex, which may be involved in the regulation of bacterial
maltose transport. Overall, our findings indicate the important role
of Kcr modification in the nutrient transport system, providing insights
into the regulatory roles of bacterial protein post-translational
modifications.