title: Resolution of an early RecA-recombination intermediate by a junction-specific endonuclease.
abstract: The nucleoprotein filament formed on a circular single strand by Escherichia coli RecA protein in vitro can pair with homologous duplex DNA even when the latter lacks a free homologous end, but subsequent progression of the reaction through strand exchange requires an end in at least one strand of the duplex DNA. We purified from E. coli an endonuclease activity that cleaves the outgoing strand of duplex DNA at the junction of homologous and heterologous sequences in three-stranded RecA-recombination intermediates. This endonuclease activity also cleaves specifically at the junctions of duplex and single-stranded regions in synthetic double-stranded oligonucleotides whose central portion consists of unpaired heterologous sequences. These activities are consistent with a role in recombination and repair of DNA.
authors.affiliation: Department of Genetics, Yale University School of Medicine, New Haven, CT, 06510, USA.
authors.forename: S K
authors.initials: SK
authors.lastname: Chiu
authors.forename: K B
authors.initials: KB
authors.lastname: Low
authors.forename: A
authors.initials: A
authors.lastname: Yuan
authors.forename: C M
authors.initials: CM
authors.lastname: Radding
mesh_terms: D001483:Base Sequence; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004260:DNA Repair; D004591:Electrophoresis, Polyacrylamide Gel; D004720:Endonucleases / Q000302:isolation & purification / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005838:Genotype; D008961:Models, Structural; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000378:metabolism; D011938:Rec A Recombinases / Q000378:metabolism*; D011995:Recombination, Genetic; D013379:Substrate Specificity
chemical_list: D009838:Oligodeoxyribonucleotides; D011938:Rec A Recombinases; D004720:Endonucleases