Cloning and characterization of a DNA gyrase A gene from Escherichia coli that confers clinical resistance to 4-quinolones
| Autor: | R. Kuroda, M. E. Cullen, A. W. Wyke, L M Fisher |
|---|---|
| Rok vydání: | 1989 |
| Předmět: |
DNA
Bacterial Nalidixic acid medicine.drug_class DNA Gyrase B Subunit Molecular Sequence Data Biology Molecular cloning medicine.disease_cause DNA gyrase DNA supercoiling activity chemistry.chemical_compound Anti-Infective Agents medicine Escherichia coli Pharmacology (medical) Cloning Molecular Pharmacology 4-Quinolones Base Sequence Drug Resistance Microbial Quinolone Molecular biology Blotting Southern Infectious Diseases DNA Topoisomerases Type II chemistry Biochemistry Genes Bacterial DNA medicine.drug Research Article |
| Zdroj: | Antimicrobial agents and chemotherapy. 33(6) |
| ISSN: | 0066-4804 |
| Popis: | Nalidixic acid, enoxacin, and other antibacterial 4-quinolones inhibit DNA gyrase activity by interrupting DNA breakage and reunion by A subunits of the A2B2 gyrase complex. Despite their clinical importance, the mode of quinolone action and mechanisms of resistance are poorly understood at the molecular level. Using a DNA fragment enrichment procedure, we isolated the gyrA gene from a uropathogenic Escherichia coli strain that encodes a gyrase A protein cross-resistant to a variety of quinolones. When complemented with gyrase B subunit, the purified A protein reconstituted DNA supercoiling activity approximately 100-fold more resistant to inhibition by enoxacin than the susceptible enzyme and failed to mediate quinolone-dependent DNA cleavage. Nucleotide sequence analysis revealed that the gene differed at 58 nucleotide positions compared with the K-12 gyrA sequence. The 875-amino-acid residue-resistant gyrase A protein differed at three positions from its wild-type E. coli K-12 counterpart: tryptophan, glutamate, and serine replaced serine, aspartate, and alanine residues at positions 83, 678, and 828, respectively. By genetic analysis of chimeric gyrA genes in a gyrA(Ts) background, we showed that the Ser-83----Trp mutation in the gyrase A protein was solely responsible for high-level bacterial resistance to nalidixic acid and fluoroquinolones. |
| Databáze: | OpenAIRE |
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