Structure of CARB-4 and AER-1 carbenicillin-hydrolyzing beta-lactamases.
Antimicrob Agents Chemother, 1998/8;42(8):1966-72.
Sanschagrin F[1], Bejaoui N, Levesque RC
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PMID: 9687391
Impact factor: 5.938
Abstract
We determined the nucleotide sequences of blaCARB-4 encoding CARB-4 and deduced a polypeptide of 288 amino acids. The gene was characterized as a variant of group 2c carbenicillin-hydrolyzing beta-lactamases such as PSE-4, PSE-1, and CARB-3. The level of DNA homology between the bla genes for these beta-lactamases varied from 98.7 to 99.9%, while that between these genes and blaCARB-4 encoding CARB-4 was 86.3%. The blaCARB-4 gene was acquired from some other source because it has a G+C content of 39.1%, compared to a G+C content of 67% for typical Pseudomonas aeruginosa genes. DNA sequencing revealed that blaAER-1 shared 60.8% DNA identity with blaPSE-3 encoding PSE-3. The deduced AER-1 beta-lactamase peptide was compared to class A, B, C, and D enzymes and had 57.6% identity with PSE-3, including an STHK tetrad at the active site. For CARB-4 and AER-1, conserved canonical amino acid boxes typical of class A beta-lactamases were identified in a multiple alignment. Analysis of the DNA sequences flanking blaCARB-4 and blaAER-1 confirmed the importance of gene cassettes acquired via integrons in bla gene distribution.
MeSH terms
Amino Acid Sequence; Base Sequence; Carbenicillin; Molecular Sequence Data; Penicillins; Sequence Alignment; Sequence Homology, Amino Acid; beta-Lactamases
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