Complex Structure of Arginine Rhamnosyltransferase EarP with Its Acceptor Elongation Factor P.

A bacterial inverting glycosyltransferase EarP transfers rhamnose from dTDP-β-l-rhamnose (TDP-Rha) to Arg32 of translation elongation factor P (EF-P) to activate its function. We report here the structural and biochemical characterization of EarP. In contrast to recently reported EarP, EarP exhibits differential conformational changes upon TDP-Rha and EF-P binding. Sugar donor binding enhances acceptor binding to EarP, as revealed by structural comparison between the apo-, TDP-Rha-, and TDP/EF-P-bound forms and isothermal titration calorimetry experiments. EF-P rhamnosylation combined with active-site geometry indicates that Asp16 corresponding to Asp20 of EarP is the catalytic base, whereas Glu272 is another putative catalytic residue. Our study should provide the basis for EarP-targeted inhibitor design against infections from and other clinically relevant species. Posttranslational rhamnosylation of EF-P plays a key role in , establishing virulence and antibiotic resistance, as well as survival. The detailed structural and biochemical characterization of the EF-P-specific rhamnosyltransferase EarP from not only demonstrates that sugar donor TDP-Rha binding enhances acceptor EF-P binding to EarP but also should provide valuable information for the structure-guided development of its inhibitors against infections from and other EarP-containing pathogens.