Penicillin-binding protein 1B

Penicillin-binding protein 1B (PBP1B) is a bifunctional enzyme in *Escherichia coli* essential for bacterial cell wall synthesis. It catalyzes peptidoglycan formation and cross-linking through transglycosylase and transpeptidase activities. PBP1B's transpeptidase domain is a major target for β-lactam antibiotics; inhibition leads to cell wall defects and bacterial death. Resistance can arise through mutations or alternative PBPs.

Other names

Murein polymerasePBP-1bpbpFponB

β-lactam antibiotics inhibit the transpeptidase activity of PBP1B by binding to the active site, leading to irreversible acylation and inactivation of the enzyme. Moenomycin inhibits the glycosyltransferase activity.