Download MendeleyX-ray analysis of the NMC-A beta-lactamase at 1.64-A resolution, a class A carbapenemase with broad substrate specificity.
Swaren, P., Maveyraud, L., Raquet, X., Cabantous, S., Duez, C., Pedelacq, J.D., Mariotte-Boyer, S., Mourey, L., Labia, R., Nicolas-Chanoine, M.H., Nordmann, P., Frere, J.M., Samama, J.P.(1998) J Biol Chem 273: 26714-26721
- PubMed: 9756914
- DOI: https://doi.org/10.1074/jbc.273.41.26714
- Primary Citation of Related Structures:
1BUE - PubMed Abstract:
The treatment of infectious diseases by penicillin and cephalosporin antibiotics is continuously challenged by the emergence and the dissemination of the numerous TEM and SHV mutant beta-lactamases with extended substrate profiles. These class A beta-lactamases nevertheless remain inefficient against carbapenems, the most effective antibiotics against clinically relevant pathogens. A new member of this enzyme class, NMC-A, was recently reported to hydrolyze at high rates, and hence destroy, all known beta-lactam antibiotics, including carbapenems and cephamycins. The crystal structure of NMC-A was solved to 1.64-A resolution, and reveals modifications in the topology of the substrate-binding site. While preserving the geometry of the essential catalytic residues, the active site of the enzyme presents a disulfide bridge between residues 69 and 238, and certain other structural differences compared with the other beta-lactamases. These unusual features in class A beta-lactamases involve amino acids that participate in enzyme-substrate interactions, which suggested that these structural factors should be related to the very broad substrate specificity of this enzyme. The comparison of the NMC-A structure with those of other class A enzymes and enzyme-ligand complexes, indicated that the position of Asn-132 in NMC-A provides critical additional space in the region of the protein where the poorer substrates for class A beta-lactamases, such as cephamycins and carbapenems, need to be accommodated.
Organizational Affiliation:
Groupe de Cristallographie Biologique, Institut de Pharmacologie et de Biologie Structurale, UPR 9062 CNRS, 205 route de Narbonne, F-31077 Toulouse CEDEX, France.
