Coupling between ATP binding and DNA cleavage by DNA topoisomerase II: A unifying kinetic and structural mechanism.

ABSTRACT: DNA topoisomerase II is a molecular machine that couples ATP hydrolysis to the transport of one DNA segment through a transient break in another segment. To learn about the energetic connectivity that underlies this coupling, we investigated how the ATPase domains exert control over DNA cleavage. We dissected the DNA cleavage reaction by measuring rate and equilibrium constants for the individual reaction steps utilizing defined DNA duplexes in the presence and absence of the nonhydrolyzable ATP analog 5'-adenylyl-beta,gamma-imidodiphosphate (AMPPNP). Our results revealed the existence of two enzyme conformations whose relative abundance is sensitive to the presence of nucleotides. The predominant species in the absence of nucleotides binds DNA at a diffusion limited rate but cannot effici

SUBMITTER: Mueller-Planitz F 

PROVIDER: S-EPMC2427340 | biostudies-literature | 2008 Jun

REPOSITORIES: biostudies-literature