The UL8 subunit of the heterotrimeric herpes simplex virus type 1 helicase-primase is required for the unwinding of single strand DNA-binding protein (ICP8)-coated DNA substrates
The UL8 subunit of the heterotrimeric herpes simplex virus type 1 helicase-primase is required for the unwinding of single strand DNA-binding protein (ICP8)-coated DNA substrates
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DOI：
10.1074/jbc.272.36.22766
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发表时间：
1997-09-05
影响因子：
4.8
通讯作者：
Lehman, IR
中科院分区：
文献类型：
--
作者：
Falkenberg, M;Bushnell, DA;Lehman, IR
单纯疱疹病毒1型原体由UL 5、UL 8和UL 52基因的产物三个亚基组成。异源三聚体酶具有DNA依赖性ATP酶、解旋酶和引发酶活性。早期的研究表明，由UL 5和UL 52基因产物组成的亚组在其解旋酶和引发酶活性方面与异源三聚体酶没有区别。我们在此证明UL 8蛋白是UL 5/52亚组在长双链DNA底物（>30个核苷酸）上的解旋酶活性所必需的，所述长双链DNA底物具有完全包被有病毒编码的单链DNA结合蛋白ICP 8的单链DNA加载位点。大肠杆菌单链PNA结合蛋白不能替代ICP 8，表明ICPS和UL 8蛋白之间存在特异性的物理相互作用。表面等离子体共振测量证明了ICP 8和UL 5/52/8异源三聚体之间的相互作用，但不与UL 5/52子组件或单独的UL 8蛋白相互作用。在ICP 8的亚饱和水平下，UL 5/52子组件确实显示解旋酶活性，表明该子组件可以结合单链DNA，但不结合ICP 8包被的DNA。
The Herpes simplex virus type 1 primosome consists of three subunits that are the products of the UL5, UL8, and UL52 genes. The heterotrimeric enzyme has DNA-dependent ATPase, helicase, and primase activities. Earlier studies show that a subassembly consisting of the UL5 and UL52 gene products was indistinguishable from the heterotrimeric enzyme in its helicase and primase activities. We demonstrate here that the UL8 protein is required for the helicase activity of the UL5/52 subassembly on long duplex DNA substrates (>30 nucleotides) with a single-stranded DNA loading site fully coated with the virus-encoded single strand DNA binding protein, ICP8. The Escherichia coli single strand PNA binding protein cannot substitute for ICP8, suggesting a specific physical interaction between ICPS and the UL8 protein. Surface plasmon resonance measurements demonstrated an interaction between ICP8 and the UL5/52/8 heterotrimer but not with the UL5/52 subassembly or the UL8 protein alone. At a subsaturating level of ICP8, the UL5/52 subassembly does show helicase activity, suggesting that the subassembly can bind to single-stranded DNA but not to ICP8-coated DNA.