期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1978
卷号：75
期号：12
页码：5960-5963
DOI：10.1073/pnas.75.12.5960
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：DNA gyrase has been purified to near homogeneity from Escherichia coli. The enzyme consists of two subunits of molecular weights 90,000 and 100,000 present in roughly equimolar amounts. The subunits can be identified as the products of two genes, determining resistance to coumermycin A1 and novobiocin (cou) and to nalidixic acid and oxolinic acid (nalA), respectively. These antibiotics were previously shown to be specific inhibitors of DNA gyrase. The ATPase activity of DNA gyrase is stimulated by double-stranded DNA and strongly inhibited by novobiocin but is relatively insensitive to oxolinic acid. Covalent attachment of an ATP derivative to the smaller (coumermycin-specific) subunit is also inhibited by novobiocin, suggesting that this drug interferes with the energy-coupling aspect of the DNA supercoiling reaction by blocking the access of ATP to the enzyme.
