THE 43-KILODALTON N-TERMINAL FRAGMENT OF THE DNA GYRASE-B PROTEIN HYDROLYZES ATP AND BINDS COUMARIN DRUGS
THE 43-KILODALTON N-TERMINAL FRAGMENT OF THE DNA GYRASE-B PROTEIN HYDROLYZES ATP AND BINDS COUMARIN DRUGS
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DOI：
10.1021/bi00061a033
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发表时间：
1993-03-16
期刊：
影响因子：
2.9
通讯作者：
MAXWELL, A
中科院分区：
文献类型：
--
作者：
ALI, JA;JACKSON, AP;MAXWELL, A
我们克隆并过表达了一个编码43 kDa蛋白的基因，该蛋白对应于DNA旋转酶B亚基的N-末端片段。我们发现这种蛋白可以水解三磷酸腺苷，并与香豆素类药物结合。ATP的水解表现出明显的非Michaelis-Menten动力学，并与蛋白质的活性形式为二聚体的方案一致，这一结论得到了分子量研究的支持。香豆素类药物与43 kDa的片段结合非常紧密，新霉素与蛋白质单体结合，而香豆素A1明显诱导二聚体的形成。讨论了这些结果对DNA旋转酶的超螺旋机制和香豆素类药物抑制旋转酶b的意义。
We have cloned and overexpressed a gene encoding a 43-kDa protein corresponding to the N-terminal fragment of the DNA gyrase B subunit. We show that this protein hydrolyzes ATP and binds coumarin drugs. The hydrolysis of ATP shows distinctly non-Michaelis-Menten kinetics and is consistent with a scheme in which the active form of the protein is a dimer, a conclusion supported by molecular weight studies. The coumarin drugs bind very tightly to the 43-kDa fragment, with novobiocin binding to the protein monomer and coumermycin A1 apparently inducing the formation of a dimer. The implications of these results with respect to the mechanism of supercoiling by DNA gyrase and the inhibition of gyrase b coumarin drugs are discussed.