1BMC

STRUCTURE OF A ZINC METALLO-BETA-LACTAMASE FROM BACILLUS CEREUS

Summary for 1BMC

• Entry DOI: 10.2210/pdb1bmc/pdb
• Descriptor: METALLO-BETA-LACTAMASE, ZINC ION (3 entities in total)
• Functional Keywords: hydrolase (acting in cyclic amides), antibiotic resistance
• Biological source: Bacillus cereus
• Cellular location: Periplasm : P04190
• Total number of polymer chains: 1
• Total formula weight: 24359.13

Authors

Carfi, A.,Pares, S.,Duee, E.,Dideberg, O. (deposition date: 1995-06-16, release date: 1996-08-28, Last modification date: 2024-02-07)

Primary citation

Carfi, A.,Pares, S.,Duee, E.,Galleni, M.,Duez, C.,Frere, J.M.,Dideberg, O.
The 3-D structure of a zinc metallo-beta-lactamase from Bacillus cereus reveals a new type of protein fold.
EMBO J., 14:4914-4921, 1995

PubMed Abstract: The 3-D structure of Bacillus cereus (569/H/9) beta-lactamase (EC 3.5.2.6), which catalyses the hydrolysis of nearly all beta-lactams, has been solved at 2.5 A resolution by the multiple isomorphous replacement method, with density modification and phase combination, from crystals of the native protein and of a specially designed mutant (T97C). The current model includes 212 of the 227 amino acid residues, the zinc ion and 10 water molecules. The protein is folded into a beta beta sandwich with helices on each external face. To our knowledge, this fold has never been observed. An approximate internal molecular symmetry is found, with a 2-fold axis passing roughly through the zinc ion and suggesting a possible gene duplication. The active site is located at one edge of the beta beta sandwich and near the N-terminal end of a helix. The zinc ion is coordinated by three histidine residues (86, 88 and 149) and a water molecule. A sequence comparison of the relevant metallo-beta-lactamases, based on this protein structure, highlights a few well-conserved amino acid residues. The structure shows that most of these residues are in the active site. Among these, aspartic acid 90 and histidine 210 participate in a proposed catalytic mechanism for beta-lactam hydrolysis.

PubMed: 7588620

Experimental method

X-RAY DIFFRACTION (2.5 Å)