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Kinetic and spectroscopic characterization of native and metal‐substituted β‐lactamase from Aeromonas hydrophila AE036

2000; Wiley; Volume: 467; Issue: 2-3 Linguagem: Inglês

10.1016/s0014-5793(00)01102-9

1873-3468

Maria Hernandez-Valladares, Martin Kiefer, Uwe Heinz, Raquel Paul Soto, Wolfram Meyer‐Klaucke, Hans F. Nolting, Michael Zeppezauer, M. Galleni, Jean‐Marie Frère, Gian María Rossolini, Gianfranco Amicosante, Hans‐Werner Adolph,

Cassava research and cyanide

Two metal ion binding sites are conserved in metallo-beta-lactamase from Aeromonas hydrophila. The ligands of a first zinc ion bound with picomolar dissociation constant were identified by EXAFS spectroscopy as one Cys, two His and one additional N/O donor. Sulfur-to-metal charge transfer bands are observed for all mono- and di-metal species substituted with Cu(II) or Co(II) due to ligation of the single conserved cysteine residue. Binding of a second metal ion results in non-competitive inhibition which might be explained by an alternative kinetic mechanism. A possible partition of metal ions between the two binding sites is discussed.