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A novel metallo‐β‐lactamase, Mbl1b, produced by the environmental bacterium Caulobacter crescentus 1
Author(s) -
Simm Alan M.,
Higgins Catherine S.,
Pullan Steven T.,
Avison Matthew B.,
Niumsup Pannika,
Erdozain Olivia,
Bennett Peter M.,
Walsh Timothy R.
Publication year - 2001
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)03152-0
Subject(s) - caulobacter crescentus , homotetramer , escherichia coli , microbiology and biotechnology , cefoxitin , enzyme kinetics , imipenem , chemistry , enzyme , biology , biochemistry , bacteria , gene , active site , antibiotics , genetics , antibiotic resistance , protein subunit , bacterial protein , staphylococcus aureus
Caulobacter crescentus 101123 possesses a gene ( Mbl1b ) encoding a metallo‐β‐lactamase with 32% amino acid identity to the L1 metallo‐β‐lactamase from Stenotrophomonas maltophilia . The gene was cloned into an expression vector and the enzyme, Mbl1b, was expressed in Escherichia coli . Mbl1b was purified. Catalytic properties for several antibiotics were determined. The enzyme exhibits Michaelis–Menten kinetics for imipenem, meropenem and nitrocefin but substrate inhibition kinetics with cefoxitin, cefaloridine, penicillin G and ampicillin. A homology model predicts Mbl1b has the same structural fold as other metallo‐β‐lactamases with a detailed structure very similar to L1 but whereas L1 is a homotetramer, Mbl1b is monomeric. The main differences between Mbl1 and L1 are in the N‐terminal region.