title: Nalidixic acid-resistant mutations of the gyrB gene of Escherichia coli.
abstract: DNA fragments of 3.4 kb containing the gyrB gene were cloned from Escherichia coli KL-16 and from spontaneous nalidixic acid-resistant mutants. The mutations (nal-24 and nal-31) had been determined to be in the gyrB gene by transduction analysis. Nucleotide sequence analysis of the cloned DNA fragments revealed that nal-24 was a G to A transition at the first base of the 426th codon of the gyrB gene, resulting in an amino acid change from aspartic acid to asparagine, and nal-31 was an A to G transition at the first base of the 447th codon, resulting in an amino acid change from lysine to glutamic acid. This indicates tha mutations in the gyrB gene are responsible for nalidixic acid resistance.
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes; D004250:DNA Topoisomerases, Type II / Q000235:genetics*; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D005796:Genes; D005798:Genes, Bacterial; D009154:Mutation; D009268:Nalidixic Acid / Q000494:pharmacology*; D010957:Plasmids
chemical_list: D009268:Nalidixic Acid; D004262:DNA Restriction Enzymes; D004250:DNA Topoisomerases, Type II