Hamatake R K, Bifano M, Hurlburt W W, Tenney D J
Department of Virology, Bristol-Myers Squibb Pharmaceutical Research Institute, Wallingford, CT 06492, USA.
J Gen Virol. 1997 Apr;78 ( Pt 4):857-65. doi: 10.1099/0022-1317-78-4-857.
The herpes simplex virus type 1 (HSV) single-stranded DNA-binding protein (SSB, ICP8) stimulates the viral DNA polymerase (Pol) on an oligonucleotide-primed single-stranded DNA template. This stimulation is non-specific since other SSBs also increase Pol activity. However, only ICP8 was stimulatory when Pol activity was dependent upon priming by the viral helicase-primase complex. ICP8 also specifically stimulated the primer synthesis and ATPase activities of the helicase-primase. The mechanism of stimulation was different from that of Pol; helicase-primase stimulation required much lower amounts of ICP8 than the amount that saturates the DNA and optimally stimulates Pol. Furthermore, ICP8 did not act by removing secondary structure as stimulation also occurred on homopolymer templates. While the UL8 component of the helicase-primase is not required for enzymatic activities by a subassembly of the UL5 and UL52 proteins, only the holoenzyme (UL5/8/52) was stimulated by ICP8. These results identify a unique, functional interaction between the ICP8 SSB and the helicase-primase complex, mediated by the UL8 subunit.
单纯疱疹病毒1型（HSV）单链DNA结合蛋白（SSB，ICP8）在寡核苷酸引发的单链DNA模板上刺激病毒DNA聚合酶（Pol）。这种刺激是非特异性的，因为其他单链结合蛋白也会增加Pol的活性。然而，当Pol活性依赖于病毒解旋酶-引发酶复合物引发时，只有ICP8具有刺激作用。ICP8还特异性地刺激了解旋酶-引发酶的引物合成和ATP酶活性。刺激机制与Pol不同；解旋酶-引发酶刺激所需的ICP8量比使DNA饱和并最佳刺激Pol所需的量低得多。此外，ICP8并非通过去除二级结构起作用，因为在同聚物模板上也会发生刺激。虽然解旋酶-引发酶的UL8组分对于由UL5和UL52蛋白的亚组装体进行的酶活性不是必需的，但只有全酶（UL5/8/52）受到ICP8的刺激。这些结果确定了由UL8亚基介导的ICP8单链结合蛋白与解旋酶-引发酶复合物之间独特的功能相互作用。
