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Nucleotide sequence and characterization of a carbenicillin-hydrolyzing penicillinase gene from Proteus mirabilis
Y Sakurai1, K Tsukamoto, T Sawai
1Division of Microbial Chemistry, Faculty of Pharmaceutical Sciences, Chiba University, Japan.
Abstract:
The structural gene of a carbenicillinase was cloned from the chromosomal DNA of Proteus mirabilis GN79. This gene codes for a protein of 270 amino acids. Alignment of the amino acid sequence with those of known beta-lactamases revealed that the enzyme is a novel class A beta-lactamase with a unique conserved triad, RTG. By using a DNA fragment of the structural gene, a lack of cross hybridization was confirmed between the DNA probe and total DNAs from natural isolates of P. mirabilis, suggesting that the carbenicillinase may not be a species-specific beta-lactamase of P. mirabilis.
Insights
Researchers cloned the carbenicillinase gene from Proteus mirabilis, identifying a novel class A beta-lactamase. This enzyme may not be specific to P. mirabilis, indicating broader implications for antibiotic resistance research.
Area of Science:
- Microbiology
- Molecular Biology
- Biochemistry
Background:
- Beta-lactamase enzymes confer antibiotic resistance.
- Carbenicillinase, a type of beta-lactamase, is crucial in understanding resistance mechanisms.
- Proteus mirabilis is a known bacterium carrying resistance genes.
Purpose of the Study:
- To clone and characterize the structural gene for carbenicillinase from Proteus mirabilis GN79.
- To determine the class and unique features of the resulting beta-lactamase enzyme.
- To investigate the species specificity of the identified carbenicillinase.
Main Methods:
- Cloning of the structural gene from chromosomal DNA.
- Amino acid sequence alignment with known beta-lactamases.
- DNA hybridization techniques using a DNA fragment probe.
Main Results:
- The structural gene codes for a 270-amino acid protein.
- The enzyme is identified as a novel class A beta-lactamase with a unique RTG conserved triad.
- DNA hybridization confirmed the carbenicillinase gene is not species-specific to P. mirabilis isolates.
Conclusions:
- A novel class A beta-lactamase with unique features has been identified.
- The carbenicillinase identified in this study is likely not specific to Proteus mirabilis.
- Findings contribute to understanding the evolution and spread of antibiotic resistance genes.