title: Rec-A protein-mediated irreversible fixation of an oligodeoxyribonucleotide to specific site in DNA.
abstract: RecA protein can polymerize on an oligodeoxyribonucleotide to form a filament that finds its homologous sequence in double-stranded DNA. When such an oligonucleotide is linked to psoralen, a photoactivatable DNA intercalator, it irreversibly binds to the homologous site in double stranded DNA as a result of psoralen photoadduct formation at thymidines. The relative efficiency of specific vs. nonspecific binding of an oligonucleotide depended upon the ratio of psoralenated oligonucleotide to total DNA. Na+ ions at concentrations greater than 50 mM eliminated specific binding. Under optimal conditions. the probability of binding of an 80-mer oligonucleotide to a specific site was > 10(5) times greater than that of binding to any single nonspecific site. Under the conditions described, RecA-mediated photoadduction was equally efficient with superhelical and linear double-stranded DNA.
authors.affiliation: Yale University School of Medicine, Department of Genetics, New Haven, CT 06510, USA.
authors.forename: E I
authors.initials: EI
authors.lastname: Golub
authors.forename: P M
authors.initials: PM
authors.lastname: Glazer
authors.forename: D C
authors.initials: DC
authors.lastname: Ward
authors.forename: C M
authors.initials: CM
authors.lastname: Radding
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D018736:DNA Adducts / Q000096:biosynthesis*; D005363:Ficusin / Q000378:metabolism*; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism*; D011938:Rec A Recombinases / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid
chemical_list: D018736:DNA Adducts; D009838:Oligodeoxyribonucleotides; D011938:Rec A Recombinases; D005363:Ficusin