Molecular Mechanisms of General Genetic Recombination: The DNA-binding Sites of RecA Protein
This extract was created in the absence of an abstract.
Excerpt
The RecA protein of Escherichia coli mediates homologous pairing and strand exchange reactions similar to those of general genetic recombination. In vitro, this protein acts on suitable DNA molecules from phages or plasmids, converting them to heteroduplex recombination intermediates. We describe studies on RecA-mediated, reciprocal strand exchanges between two duplexes. Homologous pairing can occur if one duplex is partially single stranded (gapped) and leads to a strand exchange capable of passing and contributing to the repair of a two-strand break in the fully duplex molecule. However, it fails to pass a break in the gapped duplex. In related studies, we show that homologous pairing leading to strand exchange can occur between DNA molecules at positions where both are duplex.
Using electron microscopy and image reconstruction methods, we demonstrate that DNA-RecA spiral filaments contain a single deep groove. We suggest that RecA monomers have binding sites for two DNA chains and...
