Single-stranded DNA binding protein and DNA helicase of bacteriophage T7 mediate homologous DNA strand exchange.
Two proteins encoded by bacteriophage T7, the gene 2.5 single-stranded DNA binding protein and the gene 4 helicase, mediate homologous DNA strand exchange. Gene 2.5 protein stimulates homologous base pairing of two DNA molecules containing complementary single-stranded regions. The formation of a joint molecule consisting of circular, single-stranded M13 DNA, annealed to homologous linear, duplex DNA having 3'- or 5'-single-stranded termini of approximately 100 nucleotides requires stoichiometric amounts of gene 2.5 protein. In the presence of gene 4 helicase, strand transfer proceeds at a rate of > 120 nucleotides/s in a polar 5' to 3' direction with respect to the invading strand, resulting in the production of circular duplex M13 DNA. Strand transfer is coupled to the hydrolysis of a nucleoside 5'-triphosphate. The reaction is dependent on specific interactions between gene 2.5 protein and gene 4 protein.
Kong
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Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
Richardson
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CC
D017123:Bacteriophage T7 / Q000235:genetics* / Q000378:metabolism*; D004265:DNA Helicases / Q000235:genetics* / Q000378:metabolism*; D019915:DNA Primase; D004279:DNA, Viral / Q000235:genetics* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D008957:Models, Genetic; D011485:Protein Binding; D012316:RNA Nucleotidyltransferases / Q000235:genetics* / Q000378:metabolism*; D011995:Recombination, Genetic; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism*
D004279:DNA, Viral; D004268:DNA-Binding Proteins; D014764:Viral Proteins; C085913:gene 2.5 protein, Enterobacteria phage T7; D019915:DNA Primase; D012316:RNA Nucleotidyltransferases; D004265:DNA Helicases