title: Bacteriophage T5 gene D10 encodes a branch-migration protein.
abstract: Helicases catalyze the unwinding of double-stranded nucleic acids where structure and phosphate backbone contacts, rather than nucleobase sequence, usually determines substrate specificity. We have expressed and purified a putative helicase encoded by the D10 gene of bacteriophage T5. Here we report that this hitherto uncharacterized protein possesses branch migration and DNA unwinding activity. The initiation of substrate unwinding showed some sequence dependency, while DNA binding and DNA-dependent ATPase activity did not. DNA footprinting and purine-base interference assays demonstrated that D10 engages these substrates with a defined polarity that may be established by protein-nucleobase contacts. Bioinformatic analysis of the nucleotide databases revealed genes predicted to encode proteins related to D10 in archaebacteria, bacteriophages and in viruses known to infect a range of eukaryotic organisms.
authors.affiliation: Department of Oncology &Metabolism, University of Sheffield Medical School, Beech Hill Rd, Sheffield, S10 2RX, UK.|Department of Infection, Immunity &Cardiovascular Disease, University of Sheffield Medical School, Beech Hill Rd, Sheffield, S10 2RX, UK.
authors.forename: Io Nam
authors.initials: IN
authors.lastname: Wong
authors.affiliation: Department of Infection, Immunity &Cardiovascular Disease, University of Sheffield Medical School, Beech Hill Rd, Sheffield, S10 2RX, UK.|Sheffield Institute for Nucleic Acids, University of Sheffield Medical School, Beech Hill Rd, Sheffield, S10 2RX, UK.
authors.forename: Jon R
authors.initials: JR
authors.lastname: Sayers
authors.affiliation: Department of Oncology &Metabolism, University of Sheffield Medical School, Beech Hill Rd, Sheffield, S10 2RX, UK.|Sheffield Institute for Nucleic Acids, University of Sheffield Medical School, Beech Hill Rd, Sheffield, S10 2RX, UK.
authors.forename: Cyril M
authors.initials: CM
authors.lastname: Sanders
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics; D001105:Archaea / Q000235:genetics; D019295:Computational Biology / Q000379:methods; D004247:DNA / Q000235:genetics; D018983:DNA Footprinting / Q000379:methods; D004265:DNA Helicases / Q000235:genetics; D004277:DNA, Single-Stranded / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D009711:Nucleotides / Q000235:genetics; D013379:Substrate Specificity; D013604:T-Phages / Q000235:genetics*; D014764:Viral Proteins / Q000235:genetics*
chemical_list: D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D009711:Nucleotides; D014764:Viral Proteins; D004247:DNA; D000251:Adenosine Triphosphatases; D004265:DNA Helicases