Engineered Mononuclear Variants in Bacillus cereus Metallo-beta-lactamase BcII Are Inactive
Metallo-{beta}-lactamases (M{beta}Ls) are zinc enzymes able to hydrolyze almost all {beta}-lactam antibiotics, rendering them inactive, at the same time endowing bacteria high levels of resistance. The design of inhibitors active against all classes of M{beta}Ls has been hampered by their structural diversity and by the heterogeneity in metal content in enzymes from different sources. BcII is the metallo-{beta}-lactamase from Bacillus cereus, which is found in both the mononuclear and dinuclear forms. Despite extensive studies, there is still controversy about the nature of the active BcII species. Here we have designed two mutant enzymes in which each one of the metal binding sites was selectively removed. Both mutants were almost inactive, despite preserving most of the structural features of each metal site. These results reveal that neither site isolated in the M{beta}L scaffold is sufficient to render a fully active enzyme. This suggests that only the dinuclear species is active or that the mononuclear variants can be active only if aided by other residues that would be metal ligands in the dinuclear species.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 959827
- Report Number(s):
- BNL-82813-2009-JA; BICHAW; TRN: US201016%%971
- Journal Information:
- Biochemistry, Vol. 47, Issue 33; ISSN 0006-2960
- Country of Publication:
- United States
- Language:
- English
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