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Homologous DNA pairing promoted by a 20-amino acid peptide derived from RecA
O N Voloshin1, L Wang, R D Camerini-Otero
1National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1810, USA.
Abstract:
The molecular structure of the Escherichia coli RecA protein in the absence of DNA revealed two disordered or mobile loops that were proposed to be DNA binding sites. A short peptide spanning one of these loops was shown to carry out the key reaction mediated by the whole RecA protein: pairing (targeting) of a single-stranded DNA to its homologous site on a duplex DNA. In the course of the reaction the peptide bound to both substrate DNAs, unstacked the single-stranded DNA, and assumed a beta structure. These events probably recapitulate the underlying molecular pathway or mechanism used by homologous recombination proteins.