Biopolymers and cell. 1988. Volume 4. № 3. 119 - 123

A. I. Slesarev, S. A. Kozjavkin

SUBSTRATE SPECIFICITY AND BIOLOGICAL ROLE OF REVERSE GYRASE FROM EXTREME THERMOPHILIC ARCHAEBACTERIA

Summary

    Reverse gyrase has been isolated from new archaebacterium D. amylolythicus. It was found that single-stranded DNA was effective in inhibiting the action of reverse gyrase. Using heteroduplex molecules formed from a pair of plasmids, one of which contains a small insertion relative to the other, it is shown that enzyme introduces additional positive supercoils into positively supercoiled DNA if a short single-stranded loop is placed in the DNA. These results suggest that reverse gyrase is specific to single-stranded DNA like eubacterial topoisomerase I. Due to such specificity reverse gyrase can support optimal level of positive supercoiling in extreme thermophiles and prevents denaturation of the gcnomic DNA of these organisms.