Ryan M J
Biochemistry. 1976 Aug 24;15(17):3769-77. doi: 10.1021/bi00662a020.
Coumermycin A1, an antibiotic related to novobiocin, inhibited nucleic acid synthesis in intact Escherichia coli with replication being slightly more sensitive to this drug than transcription. The ultraviolet-induced repair synthesis of DNA was only partially inhibited under conditions where replication was eliminated by coumermycin A1. Inhibition of protein synthesis was a secondary effect. Coumermycin A1-resistant E. coli were isolated and the mutation was mapped near dnaA. Chromatography of crude protein extracts of sensitive and resistant bacteria on drug affinity columns implicated a soluble protein of approximately 37,000 molecular weight as the target site for coumermycin A1. Depending on the medium used, this antibiotic had either a bacteriocidal or a bacteriostatic effect on E. coli. Results showed that the effect of coumermycin A1 cannot be explained by the degradation of DNA under bacteriocidal growth conditions.
香豆霉素A1是一种与新生霉素相关的抗生素，它能抑制完整大肠杆菌中的核酸合成，其中复制过程对该药物的敏感性略高于转录过程。在香豆霉素A1消除复制的条件下，紫外线诱导的DNA修复合成仅受到部分抑制。蛋白质合成的抑制是一种次要效应。分离出了对香豆霉素A1具有抗性的大肠杆菌，并将该突变定位在dnaA附近。在药物亲和柱上对敏感菌和抗性菌的粗蛋白提取物进行色谱分析，结果表明，一种分子量约为37,000的可溶性蛋白是香豆霉素A1的靶位点。根据所使用的培养基不同，这种抗生素对大肠杆菌要么具有杀菌作用，要么具有抑菌作用。结果表明，在杀菌生长条件下，香豆霉素A1的作用不能通过DNA降解来解释。
