Holliday junction dynamics and branch migration: single-molecule analysis.

ABSTRACT: The Holliday junction (HJ) is a central intermediate in various genetic processes including homologous and site-specific recombination and DNA replication. Branch migration allows the exchange between homologous DNA regions, but the detailed mechanism for this key step of DNA recombination is unidentified. Here, we report direct real-time detection of branch migration in individual molecules. Using appropriately designed HJ constructs we were able to follow junction branch migration at the single-molecule level. Branch migration is detected as a stepwise random process with the overall kinetics dependent on Mg2+ concentration. We developed a theoretical approach to analyze the mechanism of HJ branch migration. The data show steps in which the junction flips between conformations favorable

SUBMITTER: Karymov M 

PROVIDER: S-EPMC1140338 | biostudies-literature | 2005 Jun

REPOSITORIES: biostudies-literature