Homologous DNA Pairing Promoted by a 20-Amino Acid Peptide Derived from RecA

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Science  10 May 1996:
Vol. 272, Issue 5263, pp. 868-872
DOI: 10.1126/science.272.5263.868


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 β structure. These events probably recapitulate the underlying molecular pathway or mechanism used by homologous recombination proteins.

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