Escherichia coli DNA Gyrase
The role of DNA gyrase -a type II topoisomerase- had been speculated about for a long time before the discovery of the enzyme. In 1963, J. Cairns (1) pointed out that the Escherichia coli chromosome is a closed circular double strand DNA molecule. It has consequently become apparent that a replication machinery which has to unwind the two strands would generate a positive swivel in front of the advancing replication fork. A topoisomerase type II could, therefore, release this tension. The second problem relating to DNA gyrase was the observation that coumarins, e.g. novobiocin, and drugs like nalidixic acid inhibit the B and the A subunits of gyrase respectively. Previous studies have already shown that these drugs also block DNA replication in vivo. It is therefore not too surprising that the role of this enzyme seemed clear when it was discovered by M. Geliert and Colleagues at the N.I.H. (2). This picture however, turned out to be more complicated when further studies revealed that the two families of drugs inhibit many other cellular processes, all dependent on the DNA template. DNA gyrase has now become a most promiscuous protein, participating in different molecular pathways such as replication, transcription, transposition and recombination (for review see 3).
KeywordsCell Free Extract Nalidixic Acid Oxolinic Acid Solid Phase Radioimmunoassay Gyrase Inhibitor
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- 19.Lother, H., Bunk, H.J., Morelli, C., Heimann, B., Chakraborty, T. and Messer, W. (1981) ICN-UCLA symp. Mol. and Cell. Biol. 22, 57.Google Scholar
- 23.Kano, J., Miyashita, T., Nakamura, H., Kuraki, K., Nagata, A. and Imamoto, F. (1981) 13, 173.Google Scholar