UTP is a cofactor for the DNA strand exchange reaction performed by the RecA protein of Escherichia coli

Piero R. Bianco, George M. Weinstock

Research output: Contribution to journalArticlepeer-review


The RecA protein of Escherichia coli is required for homologous genetic recombination and induction of the SOS regulon. In order for RecA protein to function in these two roles, a nucleoside triphosphate cofactor, usually ATP or dATP, is required. We have examined the ability of UTP to substitute for (r,d)ATP as nucleoside triphosphate cofactor. We have found that although UTP is hydrolyzed by RecA protein in the presence of long DNA molecules, it is not hydrolyzed in reactions in which the cofactors are oligodeoxyribonucleotides less than ~50 nt in length. We show that UTP can efficiently substitute for ATP as nucleoside triphosphate cofactor for the DNA strand exchange reaction in vitro. The RecA1332 protein (Cys129 → Met), which was originally shown to be defective for homologous recombination in vivo, is able to perform DNA strand exchange in vitro with ATP, but is unable to do so with UTP. These results suggest that UTP may be a cofactor for DNA strand exchange in vivo. The inability of RecA protein to hydrolyze UTP with oligodeoxyribonucleotides as cofactor and the ability of RecA to utilize UTP as cofactor in DNA strand exchange suggest a separation of the functions of RecA protein into those that require exclusively ATP and those which can utilize additional nucleoside triphosphate cofactors.

Original languageEnglish (US)
Pages (from-to)7313-7320
Number of pages8
Issue number20
StatePublished - May 19 1998
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry


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