title: Strand annealing and terminal transferase activities of a B-family DNA polymerase.
abstract: DNA replication polymerases have the inherent ability to faithfully and rapidly copy a DNA template according to precise Watson-Crick base pairing. The primary B-family DNA replication polymerase (Dpo1) in the hyperthermophilic archaeon, Sulfolobus solfataricus, is shown here to possess a remarkable DNA stabilizing ability for maintaining weak base pairing interactions to facilitate primer extension. This thermal stabilization by Dpo1 allowed for template-directed synthesis at temperatures more than 30 °C above the melting temperature of naked DNA. Surprisingly, Dpo1 also displays a competing terminal deoxynucleotide transferase (TdT) activity unlike any other B-family DNA polymerase. Dpo1 is shown to elongate single-stranded DNA in template-dependent and template-independent manners. Experiments with different homopolymeric templates indicate that initial deoxyribonucleotide incorporation is complementary to the template. Rate-limiting steps that include looping back and annealing to the template allow for a unique template-dependent terminal transferase activity. The multiple activities of this unique B-family DNA polymerase make this enzyme an essential component for DNA replication and DNA repair for the maintenance of the archaeal genome at high temperatures.
authors.affiliation: Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA.
authors.forename: Zhongfeng
authors.initials: Z
authors.lastname: Zuo
authors.forename: Hsiang-Kai
authors.initials: HK
authors.lastname: Lin
authors.forename: Michael A
authors.initials: MA
authors.lastname: Trakselis
mesh_terms: D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism; D020029:Base Pairing; D004253:DNA Nucleotidylexotransferase / Q000235:genetics / Q000378:metabolism*; D004261:DNA Replication; D004277:DNA, Single-Stranded; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism*; D020745:Genome, Archaeal; D007700:Kinetics; D013696:Temperature
chemical_list: D019843:Archaeal Proteins; D004277:DNA, Single-Stranded; D004253:DNA Nucleotidylexotransferase; D004259:DNA-Directed DNA Polymerase