The metallo-beta-lactamase VIM-4, mainly found in Pseudomonas aeruginosa or Acinetobacter baumannii, was produced in Escherichia coli and characterized by biochemical and X-ray techniques. A detailed kinetic study performed in the presence of Zn(2+) at concentrations ranging from 0.4 to 100 mu M showed that VIM-4 exhibits a kinetic profile similar to the profiles of VIM-2 and VIM-1. However, VIM-4 is more active than VIM-1 against benzylpenicillin, cephalothin, nitrocefin, and imipenem and is less active than VIM-2 against ampicillin and meropenem. The crystal structure of the dizinc form of VIM-4 was solved at 1.9 angstrom. The sole difference between VIM-4 and VIM-1 is found at residue 228, which is Ser in VIM-1 and Arg in VIM-4. This substitution has a major impact on the VIM-4 catalytic efficiency compared to that of VIM-1. In contrast, the differences between VIM-2 and VIM-4 seem to be due to a different position of the flapping loop and two substitutions in loop 2. Study of the thermal stability and the activity of the holo-and apo-VIM-4 enzymes revealed that Zn(2+) ions have a pronounced stabilizing effect on the enzyme and are necessary for preserving the structure.
|Titolo:||Biochemical and structural characterization of the subclass B1 metallo-β-lactamase VIM-4.|
|Rivista:||ANTIMICROBIAL AGENTS AND CHEMOTHERAPY|
|Citazione:||Lassaux, P., Traoré, D.a., Loisel, E., Favier, A., Docquier, J.D., Sohier, J.s., et al. (2011). Biochemical and structural characterization of the subclass B1 metallo-β-lactamase VIM-4. ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, 55(3), 1248-1255.|
|Appare nelle tipologie:||1.1 Articolo in rivista|
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