• YjgM is a novel crotonyltransferase critical for polymyxin resistance of Escherichia coli

Lysine crotonylation has attracted widespread attention in recent years. However, little is known about bacterial crotonylation, particularly crotonyltransferase and decrotonylase, and how it affects antibiotic resistance. Our study demonstrated the ubiquitous presence of crotonylation in E.coli and its connection to bacterial resistance to polymyxin. We first identified the crotonyltransferase YjgM and its regulatory pathways in E. coli with a focus on crotonylation. Further studies suggested that YjgM upregulates the crotonylation of the substrate protein PmrA, which is crucial for controlling E. coli's resistance to polymycin, thereby boosting PmrA's affinity for binding to the promoter of eptA, which in turn promotes EptA expression and confers polymyxin resistance in E. coli. Additionally, we discovered that PmrA's crucial crotonylation site and functional site is Lys 164. These significant discoveries highlight the role of crotonylation in bacterial drug resistance and offer a fresh perspective for creating antibacterial medicines.