The three-dimensional structure of VIM-2, a Zn-beta-lactamase from Pseudomonas aeruginosa in its reduced and oxidised form.
The crystal structures of the universally widespread metallo-beta-lactamase (MBL) Verona integron-encoded MBL (VIM)-2 from Pseudomonas aeruginosa have been solved in their native form as well as in an unexpected oxidised form. This carbapenem-hydrolysing enzyme belongs to the so-called B1 subfamily of MBLs and shares the folding of alpha beta/beta alpha sandwich, consisting of a core of beta-sheet surrounded by alpha-helices. Surprisingly, it showed a high tendency to be strongly oxidised at the catalytic cysteine located in the Cys site, Cys221, which, in the oxidised structure, becomes a cysteinesulfonic residue. Its native structure was obtained only in the presence of Tris(2-carboxyethyl)phosphine. This oxidation might be a consequence of a lower affinity for the second Zn located in the Cys site that would also explain the observed susceptibility of VIM-2 to chelating agents. This modification, if present in nature, might play a role in catalytic down-regulation. Comparison between native and oxidised VIM-2 and a predicted model of VIM-1 (which shows one residue different in the Cys site compared with VIM-2) is performed to explain the different activities and antibiotic specificities.
Laboratoire de Cristallographie Macromoléculaire, Institut de Biologie Structurale Jean-Pierre Ebel, CNRS-Commissariat à l'Energie Atomique (CEA)-Université Joseph Fourier, 41 rue Jules Horowitz, F-38027 Grenoble Cedex 1, France. isabel.garcia@ibs.fr
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D000595:Amino Acid Sequence; D001216:Asparagine / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry*; D001665:Binding Sites; D017124:Conserved Sequence; D003545:Cysteine / Q000737:chemistry / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D006639:Histidine / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010084:Oxidation-Reduction; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D011550:Pseudomonas aeruginosa / Q000201:enzymology*; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D015032:Zinc / Q000737:chemistry*; D001618:beta-Lactamases / Q000737:chemistry*
D001426:Bacterial Proteins; D006639:Histidine; D001216:Asparagine; D001618:beta-Lactamases; D015032:Zinc; D003545:Cysteine