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Biochemistry. 2011 Jun 14;50(23):5379-90. doi: 10.1021/bi200421g. Epub 2011 May 17.

Strand annealing and terminal transferase activities of a B-family DNA polymerase.

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1
Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA.

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.

PMID:
21545141
DOI:
10.1021/bi200421g
[Indexed for MEDLINE]
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