Peptidoglycan D,D-transpeptidase MrdA (PBP2)

Peptidoglycan D,D-transpeptidase MrdA—commonly known as penicillin-binding protein 2 (PBP2)—is an essential membrane-bound enzyme found in Gram-negative bacteria such as *Escherichia coli*. It catalyzes the cross-linking step during peptidoglycan biosynthesis by forming peptide bonds between adjacent glycan strands, which provides mechanical strength and rigidity to the bacterial cell wall. This activity is crucial for maintaining rod-shaped morphology and proper cellular growth. The inhibition of MrdA/PBP2 by β-lactam antibiotics disrupts peptidoglycan assembly, leading to loss of structural integrity and ultimately bacterial lysis. Due to its central role in cell wall synthesis and its absence from eukaryotic cells, it serves as a major therapeutic target for antibacterial agents targeting infectious diseases caused by susceptible bacteria.

Other names

Penicillin-binding protein 2PBP-2PBP2Class B penicillin-binding protein 2Transpeptidase PBP2TP PBP2EC 3.4.16.4

Inhibition of peptidoglycan cross-linking by covalent binding to the active serine residue within the transpeptidase domain. Disruption of bacterial cell wall synthesis resulting in bacteriolysis or loss of viability.