Structure and dynamics of bacterial cell wall synthases

PROJECT SUMMARY The peptidoglycan cell wall is essential for viability and growth in virtually all bacteria, and drugs that interfere with cell wall assembly are among the most effective antibiotics. Building a peptidoglycan cell wall requires precise spatiotemporal regulation of glycan strand elongation catalyzed by transglycosylase enzymes and of peptide crosslinking catalyzed by transpeptidases. Virtually all bacteria require two orthogonal families of PG synthases to accomplish cell wall assembly: bifunctional aPBPs and SEDS-bPBP two-component enzymes. Both enzymatic families are essential for growth, making them ideal antibiotic targets. In this project, we will investigate the molecular mechanisms that underlie enzymatic activation and regulation of these proteins using a combination of structural biology and single-molecule fluorescence approaches. Specifically, we will investigate 1) how structural dynamics that are central to the activation of SEDS-bPBPs are regulated by their accessory partners in vivo, and define 2) the mechanistic and structural basis that underlies allosteric activation of aPBPs by their lipoprotein cofactors. Collectively, these aims will lead to the development of a detailed mechanistic understanding of essential cell wall synthases, paving the way for future antibiotic discovery.