Yonezawa M, Takahata M, Banzawa N, Matsubara N, Watanabe Y, Narita H
Research Laboratories, Toyama Chemical Co., Ltd., Toyama, Japan.
Microbiol Immunol. 1995;39(4):243-7. doi: 10.1111/j.1348-0421.1995.tb02196.x.
Artificial mutations of Gyrase A protein (GyrA) in Escherichia coli by site-directed mutagenesis were generated to analyze quinolone-resistant mechanisms. By genetic analysis of gyrA genes in a gyrA temperature sensitive (Ts) background, exchange of Ser at the NH2-terminal 83rd position of GyrA to Trp, Leu, Phe, Tyr, Ala, Val, and Ile caused bacterial resistance to the quinolones, while exchange to Gly, Asn, Lys, Arg and Asp did not confer resistance. These results indicate that it is the most important for the 83rd amino acid residue to be hydrophobic in expressing the phenotype of resistance to the quinolones. These findings also suggest that the hydroxyl group of Ser would not play a major role in the quinolone-gyrase interaction and Ser83 would not interact directly with other amino acid residues.
通过定点诱变在大肠杆菌中产生了促旋酶A蛋白（GyrA）的人工突变，以分析喹诺酮耐药机制。通过在gyrA温度敏感（Ts）背景下对gyrA基因进行遗传分析，将GyrA氨基末端第83位的丝氨酸替换为色氨酸、亮氨酸、苯丙氨酸、酪氨酸、丙氨酸、缬氨酸和异亮氨酸会导致细菌对喹诺酮产生耐药性，而替换为甘氨酸、天冬酰胺、赖氨酸、精氨酸和天冬氨酸则不会赋予耐药性。这些结果表明，第83位氨基酸残基具有疏水性对于表达对喹诺酮的耐药表型最为重要。这些发现还表明，丝氨酸的羟基在喹诺酮-促旋酶相互作用中不会起主要作用，并且Ser83不会直接与其他氨基酸残基相互作用。
