The herpes simplex virus type-1 origin binding protein. DNA helicase activity.
The herpes simplex virus type 1 (HSV-1) origin binding protein, the product of the UL9 gene, catalyzes the unwinding of DNA in the 3'-5' direction. Helicase activity is coupled to the hydrolysis of ATP or dATP and to a lesser extent to CTP, dCTP, or UTP. It requires a divalent cation (Mg2+ > Mn2+ > Ca2+) with an optimum at 2.5 mM MgCl2. Activity is optimal at high pH (8.5-9.5) and high temperature (45 degrees C) and is inhibited at ionic strengths > 50 mM NaCl. The helicase activity is specifically stimulated by the HSV-1-encoded single-stranded DNA-binding protein, ICP8, which increases both the rate and extent of helicase activity. Helicase action appears to be stoichiometric, requiring a DNA-dependent assembly of a multimeric UL9 protein complex. Under optimal conditions, the rate of DNA unwinding is approximately 75 base pairs/min.
Department of Biochemistry, Beckman Center, Stanford University School of Medicine, California 94305-5307.
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Boehmer
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Dodson
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Lehman
D001482:Base Composition; D001483:Base Sequence; D002413:Cations, Divalent; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005814:Genes, Viral; D007700:Kinetics; D008969:Molecular Sequence Data; D009711:Nucleotides / Q000494:pharmacology; D009838:Oligodeoxyribonucleotides; D018139:Simplexvirus / Q000201:enzymology* / Q000235:genetics; D013379:Substrate Specificity; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
D002413:Cations, Divalent; D004268:DNA-Binding Proteins; D009711:Nucleotides; D009838:Oligodeoxyribonucleotides; D014764:Viral Proteins; C064565:UL9 protein, Human herpesvirus 1; D004265:DNA Helicases