The interaction of herpes simplex type 1 virus origin-binding protein (UL9 protein) with Box I, the high affinity element of the viral origin of DNA replication.
The herpes simplex type 1 (HSV-1) origin binding protein, the UL9 protein, exists in solution as a homodimer of 94-kDa monomers. It binds to Box I, the high affinity element of the HSV-1 origin, Oris, as a dimer. The UL9 protein also binds the HSV-1 single strand DNA-binding protein, ICP8. Photocross-linking studies have shown that although the UL9 protein binds Box I as a dimer, only one of the two monomers contacts Box I. It is this form of the UL9 homodimer that upon interaction with ICP8, promotes the unwinding of Box I coupled to the hydrolysis of ATP to ADP and Pi. Photocross-linking studies have also shown that the amount of UL9 protein that interacts with Box I is reduced by its interaction with ICP8. Antibody directed against the C-terminal ten amino acids of the UL9 protein inhibits its Box I unwinding activity, consistent with the requirement for interaction of the C terminus of the UL9 protein with ICP8. Inhibition by the antibody is enhanced when the UL9 protein is first bound to Box I, suggesting that the C terminus of the UL9 protein undergoes a conformational change upon binding Box I.
Lee
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Department of Biochemistry, Beckman Center, Stanford University, Stanford, California 94305-5307, USA.
Lehman
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IR
D000818:Animals; D002850:Chromatography, Gel; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism*; D019281:Dimerization; D018259:Herpesvirus 1, Human / Q000502:physiology*; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D011817:Rabbits; D018411:Spodoptera; D014764:Viral Proteins / Q000378:metabolism*; D014779:Virus Replication
D004268:DNA-Binding Proteins; C045462:ICP8 protein, Simplexvirus; D014764:Viral Proteins; C055789:origin-binding proteins, viral; C064565:UL9 protein, Human herpesvirus 1