Bacterial penicillin-binding protein 2 (PBP2)

Bacterial penicillin-binding protein 2 (PBP2) is an essential enzyme involved in the final stages of peptidoglycan synthesis within the bacterial cell wall. It catalyzes the crosslinking between glycan chains through its transpeptidase activity—a process critical for maintaining cell shape and structural integrity. PBP2 is particularly important for rod-shaped bacteria such as *Escherichia coli*, where it works with other proteins like RodA and MreB to ensure proper elongation and division. The active site contains conserved residues necessary for its enzymatic function. PBP2 serves as a primary target for β-lactam antibiotics—including ampicillin, cefaclor, cefmetazole—which bind covalently to its active site serine residue, thereby inhibiting its function and leading to bacteriolysis. Some variants exhibit unique features such as zinc ion binding that can influence stability or antibiotic susceptibility. Resistance mechanisms often involve modifications or overproduction of PBPs but do not alter their fundamental role as antibacterial targets.

Other names

PBP2Penicillin-binding protein 2

Inhibition of transpeptidase activity by covalent binding of β-lactam antibiotics to the active site serine, leading to disruption of peptidoglycan cross-linking and ultimately bacterial cell lysis or death