Abstract
Moenomycin A (MmA) belongs to a family of natural products that inhibit peptidoglycan biosynthesis by binding to the peptidoglycan glycosyltransferases, the enzymes that make the glycan chains of peptidoglycan. MmA is remarkably potent, but its clinical utility has been hampered by poor physicochemical properties. Moenomycin contains three structurally distinct regions: a pentasaccharide, a phosphoglycerate, and a C25 isoprenyl (moenocinyl) lipid tail that gives the molecule its name. The phosphoglycerate moiety links the pentasaccharide to the moenocinyl chain. This moiety contains two negatively charged groups, a phosphoryl group and a carboxylate. Both the phosphoryl group and the carboxylate have previously been implicated in target binding but the role of the carboxylate has not been explored in detail. Here we report the synthesis of six MmA analogues designed to probe the importance of the phosphoglycerate. These analogues were evaluated for antibacterial and enzyme inhibitory activity; the specific contacts between the phosphoglycerate and the protein target were assessed by X-ray crystallography in conjunction with molecular modeling. Both the phosphoryl group and the carboxylate of the phosphoglycerate chain play roles in target binding. The negative charge of the carboxylate, and not its specific structure, appears to be the critical feature in binding since replacing it with a negatively charged acylsulfonamide group produces a more active compound than replacing it with the isosteric amide. Analysis of the ligand-protein contacts suggests that the carboxylate makes a critical contact with an invariant lysine in the active site. The reported work provides information and validated computational methods critical for the design of analogues based on moenomycin scaffolds.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.