Visualizing RAD51-mediated joint molecules: implications for recombination mechanism and the effect of sequence heterology.

ABSTRACT: The defining event in homologous recombination is the exchange of base-paired partners between a single-stranded (ss) DNA and a homologous duplex driven by recombinase proteins, such as human RAD51. To understand the mechanism of this essential genome maintenance event, we analyzed the structure of RAD51-DNA complexes representing strand exchange intermediates at nanometer resolution by scanning force microscopy. Joint molecules were formed between substrates with a defined ssDNA segment and homologous region on a double-stranded (ds) partner. We discovered and quantified several notable architectural features of RAD51 joint molecules. Each end of the RAD51-bound joints had a distinct structure. Using linear substrates, a 10-nt region of mispaired bases blocked extension of joint molecules

SUBMITTER: Ristic D 

PROVIDER: S-EPMC3017611 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature