title: On the role of ATP hydrolysis in RecA protein-mediated DNA strand exchange. II. Four-strand exchanges.
abstract: RecA protein promotes a substantial DNA strand exchange reaction in the presence of adenosine 5'-O-3-(thio)triphosphate (ATP gamma S) (Menetski et al., 1990), calling into question the role of ATP hydrolysis in this reaction. We demonstrate here that the ATP gamma S-mediated process is restricted to homologous strand exchange reactions involving three strands. In four-strand exchanges between a gapped duplex circle and a second linear duplex, joint molecules are formed in the gap but are not extended into the four-strand region when ATP gamma S is present. This result provides evidence that one function of ATP hydrolysis in the recA system is to facilitate reciprocal DNA strand exchange involving four strands. Implications with respect to the role of four-stranded pairing intermediates and the mechanistic relationship between three- and four-strand exchange reactions are discussed.
authors.affiliation: Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin, Madison 53706.
authors.forename: J I
authors.initials: JI
authors.lastname: Kim
authors.forename: M M
authors.initials: MM
authors.lastname: Cox
authors.forename: R B
authors.initials: RB
authors.lastname: Inman
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D003090:Coliphages / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism* / Q000648:ultrastructure; D004926:Escherichia coli / Q000378:metabolism*; D046911:Macromolecular Substances; D008274:Magnesium / Q000494:pharmacology; D008854:Microscopy, Electron; D008961:Models, Structural; D009690:Nucleic Acid Conformation; D009692:Nucleic Acid Heteroduplexes / Q000378:metabolism* / Q000648:ultrastructure; D011938:Rec A Recombinases / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D004279:DNA, Viral; D046911:Macromolecular Substances; D009692:Nucleic Acid Heteroduplexes; C022571:adenosine 5'-O-(3-thiotriphosphate); D000255:Adenosine Triphosphate; D011938:Rec A Recombinases; D008274:Magnesium