Reverse gyrase function

The biological function of reverse gyrases is still a matter of conjecture. However, since reverse gyrases seem essential in extremely thermophilic organisms, it was postulated that these enzymes participate in the stabilization of the DNA double helix. 

This chapter describes the purification of reverse gyrases from their natural hosts and from recombinant Escherichia coli strains, in addition to the various assays developed to test their biochemical properties. Finally, the main structural features of these enzymes and their putative mechanism are discussed, together with their possible in vivo functions. 

The unique enzymatic activity of reverses gyrases, i.e., the efficient production of positively supercoiled DNA, was used by a number of authors to estimate the impact of such a DNA structure on various biological mechanisms. These include chromatin stability,recombination, and transcription. However, the in vivo role of reverse gyrases in hyperthermophiles remains a matter of speculation. It was suggested long ago that one of the main functions of topoisomerases is to tightly... 

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