Breaking down the cell wall: Strategies for antibiotic discovery targeting bacterial transpeptidases

The enzymes involved in bacterial cell wall synthesis are established antibiotic targets, and continue to be a central focus for antibiotic development. Bacterial penicillin-binding proteins (and, in some bacteria, l,d-transpeptidases) form essential peptide cross-links in the cell wall. Although the β-lactam class of antibiotics target these enzymes, bacterial resistance threatens their clinical use, and there is an urgent unmet need for new antibiotics. However, the search for new antibiotics targeting the bacterial cell wall is hindered by a number of obstacles associated with screening the enzymes involved in peptidoglycan synthesis. This review describes recent approaches for measuring the activity and inhibition of penicillin-binding proteins and l,d-transpeptidases, highlighting strategies that are poised to serve as valuable tools for high-throughput screening of transpeptidase inhibitors, supporting the development of new antibiotics.