Regulation of DNA supercoiling in Escherichia coli: Genetic basis of a compensatory mutation in DNA gyrase

FEBS Letters

Fisher, L.Mark¹  McEachern, Fiona¹ 

[1] Department of Cellular and Molecular Sciences, Division of Biochemistry, St George's Hospital Medical School, University of London, England

关键词: DNA supercoiling;    DNA gyrase;    DNA topoisomerase I;    Compensatory mutation;    (Escherichia coli);   

DOI  :  10.1016/0014-5793(89)80931-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Bacterial DNA supercoiling is controlled by balancing the supercoiling activity of DNA gyrase and the relaxing activity of DNA topoisomerase I. We have characterized the gyrB gene from a topA deletion mutant of Escherichia coli (DM800) that has a compensatory mutation in gyrB, lowering the activity of gyrase 10-fold, and thereby redressing the intracellular level of supercoiling. The mutant gene differs from the wild type in carrying three rather than two direct tandem repeats of a 6 bp sequence encoding Ala-Arg. We suggest this novel mutation affects domain spacing and was generated by an unequal crossing over event, possibly involving gyrase.

【 授权许可】

Unknown