GTP induces knotting, catenation, and relaxation of DNA by stoichiometric amounts of DNA topoisomerase II from Bombyx mori and HeLa cells.

Abstract

Type II DNA topoisomerases isolated from posterior silk glands of Bombyx mori and HeLa cells utilize ATP for unknotting of knotted DNA, relaxation of super-coiled DNA, and catenation/decatenation of circular duplex DNA under catalytic conditions. In these reactions, ATP cannot be replaced by GTP. However, GTP induces knotting, catenation, relaxation, but decatenation of circular duplex DNA by stoichiometric amounts of these enzymes. Only a limited round of the reactions proceeds with a concomitant hydrolysis of GTP and then pauses. The GTP-dependent reactions may be employed for maintenance of the knotted and/or catenated state they formed.