Mechanism of RecA-mediated homologous recombination revisited by single molecule nanomanipulation.

ABSTRACT: The mechanisms of RecA-mediated three-strand homologous recombination are investigated at the single-molecule level, using magnetic tweezers. Probing the mechanical response of DNA molecules and nucleoprotein filaments in tension and in torsion allows a monitoring of the progression of the exchange in real time, both from the point of view of the RecA-bound single-stranded DNA and from that of the naked double-stranded DNA (dsDNA). We show that strand exchange is able to generate torsion even along a molecule with freely rotating ends. RecA readily depolymerizes during the reaction, a process presenting numerous advantages for the cell's 'protein economy' and for the management of topological constraints. Invasion of an untwisted dsDNA by a nucleoprotein filament leads to an exchanged dupl

SUBMITTER: Fulconis R 

PROVIDER: S-EPMC1570433 | biostudies-literature | 2006 Sep

REPOSITORIES: biostudies-literature