Functional and biochemical analysis of a key series of ramoplanin analogues.

Ramoplanin is a potent lipoglycodepsipeptide antibiotic that is active against a wide range of Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE). It acts as an inhibitor of peptidoglycan (PG) biosynthesis that disrupts glycan chain polymerization by binding and sequestering Lipid II, a PG precursor. Herein, we report the functional antimicrobial activity (MIC, S. aureus) and fundamental biochemical assessments against a peptidoglycan glycosyltransferase (Escherichia coli PBP1b) of a set of key alanine scan analogues of ramoplanin that provide insight into the importance and role of each of its individual amino acid residues.