lambda Rap protein is a structure-specific endonuclease involved in phage recombination.
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.
Sharples
G J
GJ
Institute of Genetics, University of Nottingham, Queens Medical Centre, Nottingham NG7 2UH, United Kingdom.
Corbett
L M
LM
Graham
I R
IR
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
D004279:DNA, Viral; D016336:Gene Products, vpr; D004720:Endonucleases