Penicillin-Binding-Protein 3 (PBP3) is a periplasmic, transpeptidase enzyme which catalyses the crosslinking of peptidoglycan monomers — the last step in bacterial cell wall biosynthesis. This occurs as the PBP3 protein recognises and binds to the backbone of D-alanyl-D-alanine which occurs at the serine active site. Meropenem is an intravenous antibiotic that is used against infections such as those ofPseudomonas Aeruginosa (Pa), a novel, multi-drug resistant pathogen. Meropenem works as a competitive inhibitor of PaPBP3 due to its β-lactam ring analog that covalently binds to the serine, irreversibly inactivating the enzyme. The result is reduced rigidity in the cell wall, inevitably causing the cell to burst. Featured is PBP3 of P. Aeruginosa complexed with Meropenem. The annotations show some of the interactions important in β-lactam recognition and binding, as well as the mechanism of which some bacteria have resistance to β-lactam antibiotics.
Comments