title: lambda Rap protein is a structure-specific endonuclease involved in phage recombination.
abstract: Bacteriophage lambda encodes a number of genes involved in the recombinational repair of DNA double-strand breaks. The product of one of these genes, rap, has been purified. Truncated Rap proteins that copurify with the full-length form are derived, at least in part, from a rho-dependent transcription terminator located within its coding sequence. Full-length and certain truncated Rap polypeptides bind preferentially to branched DNA substrates, including synthetic Holliday junctions and D-loops. In the presence of manganese ions, Rap acts as an endonuclease that cleaves at the branch point of Holliday and D-loop substrates. It shows no obvious sequence preference or symmetry of cleavage on a Holliday junction. The biochemical analysis of Rap gives an insight into how recombinants could be generated by the nicking of a D-loop without the formation of a classical Holliday junction.
authors.affiliation: Institute of Genetics, University of Nottingham, Queens Medical Centre, Nottingham NG7 2UH, United Kingdom.
authors.forename: G J
authors.initials: GJ
authors.lastname: Sharples
authors.forename: L M
authors.initials: LM
authors.lastname: Corbett
authors.forename: I R
authors.initials: IR
authors.lastname: Graham
mesh_terms: D010582:Bacteriophage lambda / Q000235:genetics*; D001483:Base Sequence; D004279:DNA, Viral / Q000235:genetics*; D004720:Endonucleases / Q000235:genetics; D016336:Gene Products, vpr / Q000235:genetics*; D016334:Genes, vpr; D008969:Molecular Sequence Data; D011995:Recombination, Genetic
chemical_list: D004279:DNA, Viral; D016336:Gene Products, vpr; D004720:Endonucleases