DNA GYRASE - SUBUNIT STRUCTURE AND ATPASE ACTIVITY OF THE PURIFIED ENZYME
DNA GYRASE - SUBUNIT STRUCTURE AND ATPASE ACTIVITY OF THE PURIFIED ENZYME
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DOI：
10.1073/pnas.75.12.5960
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发表时间：
1978-01-01
影响因子：
11.1
通讯作者：
GELLERT, M
中科院分区：
文献类型：
--
作者：
MIZUUCHI, K;ODEA, MH;GELLERT, M
从大肠杆菌中纯化出的DNA旋切酶接近同源性。该酶由两个亚基组成，分子量为9万和10万，数量大致相等。亚基可鉴定为2个基因的产物，分别决定了对古霉素A1和新生物素（cou）的耐药性，以及对萘啶酸和氧喹啉酸（nalA）的耐药性。这些抗生素是DNA回转酶的特异性抑制剂。DNA旋切酶的atp酶活性受到双链DNA的刺激，并受到新生物素的强烈抑制，但对草啉酸相对不敏感。新生物素也能抑制ATP衍生物与较小的（古莫霉素特异性）亚基的共价连接，这表明该药物通过阻断ATP进入酶来干扰DNA超缠绕反应的能量偶联方面。
DNA gyrase was purified to near homogeneity from Escherichia coli. The enzyme consists of 2 subunits of MW 90,000 and 100,000 present in roughly equimolar amounts. The subunits can be identified as the products of 2 genes, determining resistance to coumermycin A1 and novobiocin (cou) and to nalidixic acid and oxolinic acid (nalA), respectively. These antibiotics were 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 it 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.