How do type II topoisomerases use ATP hydrolysis to simplify DNA topology beyond equilibrium? Investigating the relaxation reaction of nonsupercoiling type II topoisomerases.

ABSTRACT: DNA topoisomerases control the topology of DNA (e.g., the level of supercoiling) in all cells. Type IIA topoisomerases are ATP-dependent enzymes that have been shown to simplify the topology of their DNA substrates to a level beyond that expected at equilibrium (i.e., more relaxed than the product of relaxation by ATP-independent enzymes, such as type I topoisomerases, or a lower-than-equilibrium level of catenation). The mechanism of this effect is currently unknown, although several models have been suggested. We have analyzed the DNA relaxation reactions of type II topoisomerases to further explore this phenomenon. We find that all type IIA topoisomerases tested exhibit the effect to a similar degree and that it is not dependent on the supercoil-sensing C-terminal domains of the enzymes

SUBMITTER: Stuchinskaya T 

PROVIDER: S-EPMC4343537 | biostudies-literature | 2009 Feb

REPOSITORIES: biostudies-literature