2UYX

metallo-beta-lactamase (1BC2) single point mutant D120S

Summary for 2UYX

• Entry DOI: 10.2210/pdb2uyx/pdb
• Related: 1BC2 1BMC 1BVT 1DXK 1MQO 2BC2 2BFK 2BFL 2BFZ 2BG2 2BG6 2BG7 2BG8 2BGA 3BC2
• Descriptor: BETA-LACTAMASE II, GLYCEROL, ZINC ION, ... (4 entities in total)
• Functional Keywords: hydrolase, penicillinase, metal-binding, antibiotic resistance, metallo beta- lactamase
• Biological source: BACILLUS CEREUS
• Total number of polymer chains: 1
• Total formula weight: 25537.80

Authors

Larrull, L.I.,Fabiane, S.M.,Kowalski, J.M.,Bennett, B.,Sutton, B.J.,Vila, A.J. (deposition date: 2007-04-20, release date: 2007-05-08, Last modification date: 2023-12-13)

Primary citation

Llarrull, L.I.,Fabiane, S.M.,Kowalski, J.M.,Bennett, B.,Sutton, B.J.,Vila, A.J.
Asp-120 locates Zn2 for optimal metallo-beta-lactamase activity.
J. Biol. Chem., 282:18276-18285, 2007

PubMed Abstract: Metallo-beta-lactamases are zinc-dependent hydrolases that inactivate beta-lactam antibiotics, rendering bacteria resistant to them. Asp-120 is fully conserved in all metallo-beta-lactamases and is central to catalysis. Several roles have been proposed for Asp-120, but so far there is no agreed consensus. We generated four site-specifically substituted variants of the enzyme BcII from Bacillus cereus as follows: D120N, D120E, D120Q, and D120S. Replacement of Asp-120 by other residues with very different metal ligating capabilities severely impairs the lactamase activity without abolishing metal binding to the mutated site. A kinetic study of these mutants indicates that Asp-120 is not the proton donor, nor does it play an essential role in nucleophilic activation. Spectroscopic and crystallographic analysis of D120S BcII, the least active mutant bearing the weakest metal ligand in the series, reveals that this enzyme is able to accommodate a dinuclear center and that perturbations in the active site are limited to the Zn2 site. It is proposed that the role of Asp-120 is to act as a strong Zn2 ligand, locating this ion optimally for substrate binding, stabilization of the development of a partial negative charge in the beta-lactam nitrogen, and protonation of this atom by a zinc-bound water molecule.

PubMed: 17426028
DOI: 10.1074/jbc.M700742200

Experimental method

X-RAY DIFFRACTION (1.95 Å)