DNA-strand exchange promoted by RecA protein in the absence of ATP: Implications for the mechanism of energy transduction in protein-promoted nucleic acid transactions

S. C. Kowalczykowski, R. A. Krupp

Research output: Contribution to journalArticle

102 Scopus citations

Abstract

DNA-strand exchange promoted by Escherichia coli RecA protein normally requires the presence of ATP and is accompanied by ATP hydrolysis, thereby implying a need for ATP hydrolysis. Previously, ATP hydrolysis was shown not to be required; here we demonstrate furthermore that a nucleoside triphosphate cofactor is not required for DNA-strand exchange. A gratuitous allosteric effector consisting of the noncovalent complex of ADP and aluminum fluoride, ADP·AIF4/-, can both induce the high-affinity DNA-binding state of RecA protein and support the homologous pairing and exchange of up to 800- 900 bp of DNA. These results demonstrate that induction of the functionally active, high-affinity DNA-binding state of RecA protein is needed for RecA protein-promoted DNA-strand exchange and that there is no requirement for a high-energy nucleotide cofactor for the exchange of DNA strands. Consequently, the free energy needed to activate the DNA substrates for DNA- strand exchange is not derived from ATP hydrolysis. Instead, the needed free energy is derived from ligand binding and is transduced to the DNA via the associated ligand-induced structural transitions of the RecA protein-DNA complex; ATP hydrolysis simply destroys the effector ligand. This concept has general applicability to the mechanism of energy transduction by proteins.

Original languageEnglish (US)
Pages (from-to)3478-3482
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume92
Issue number8
StatePublished - 1995

ASJC Scopus subject areas

  • General
  • Genetics

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