Harnessing fluorescent moenomycin A antibiotics for bacterial cell wall imaging studies.

Abstract

The imaging of peptidoglycan (PGN) dynamics in living bacteria facilitates the understanding of PGN biosynthesis and wall-targeting antibiotics. The main tools for imaging bacterial PGN are fluorescent probes, such as well-discussed PGN metabolic labeling probes. However, the fluorescent small-molecule probes for labeling key PGN-synthesizing enzymes, especially for transglycosylases (TGases), remain to be explored. In this work, the first imaging probe labeling TGase in bacterial cell wall studies was reported. We synthesized various fluorescent MoeA-based molecules by derivatizing the natural antibiotic moenomycin A (MoeA), and used them to label TGases in living bacteria, monitor bacterial growth and division cycles by time-lapse imaging, and study cell wall growth in the mecA-carrying Methicillin-Resistant S. aureus (MRSA) strains when the β-lactam-based probes were unsuitable.