Caprazamycins: Promising lead structures acting on a novel antibacterial target MraY

The present status of antibiotic resistant requires an urgent invention of novel agents that act on clinically unexplored antibacterial targets. The enzyme MraY (phospho-MurNAc-pentapeptide translocase), essential for bacterial cell wall synthesis, fulfils this criterion as it has not been explored as a target in a clinical context. Specifically, the enzyme is involved in the lipid-linked cycle of peptidoglycan biosynthesis and is reportedly targeted by naturally-occurring nucleoside antibiotics. The antimicrobial ‘caprazamycin’ class of nucleoside antibiotics targets Mycobacterium tuberculosis and clinically relevant Gram-negative bacteria such as Pseudomonas aeruginosa besides various drug resistant strains and is therefore an eligible starting point for the development of novel agents. In this review, we aim to summarise the structure-activity relationships of the natural, semi-synthetic as well as synthetic analogues of nucleoside antibiotic caprazamycins. This review highlights caprazamycins as promising lead structures for development of potent and selective antimicrobial agents that target MraY, the bacterial enzyme involved in the first membrane-dependent step in bacterial peptidoglycan assembly.