State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China.
State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China; Changping Laboratory, Beijing 102206, China.
Mol Cell. 2023 Dec 7;83(23):4398-4412.e4. doi: 10.1016/j.molcel.2023.10.038. Epub 2023 Nov 22.
The DNA replication of mpox virus is performed by the viral polymerase F8 and also requires other viral factors, including processivity factor A22, uracil DNA glycosylase E4, and phosphoprotein H5. However, the molecular roles of these viral factors remain unclear. Here, we characterize the structures of F8-A22-E4 and F8-A22-E4-H5 complexes in the presence of different primer-template DNA substrates. E4 is located upstream of F8 on the template single-stranded DNA (ssDNA) and is catalytically active, highlighting a functional coupling between DNA base-excision repair and DNA synthesis. Moreover, H5, in the form of tetramer, binds to the double-stranded DNA (dsDNA) region downstream of F8 in a similar position as PCNA (proliferating cell nuclear antigen) does in eukaryotic polymerase complexes. Omission of H5 or disruption of its DNA interaction showed a reduced synthesis of full-length DNA products. These structures provide snapshots for the working cycle of the polymerase and generate insights into the mechanisms of these essential factors in viral DNA replication.
猴痘病毒的 DNA 复制由病毒聚合酶 F8 完成，还需要其他病毒因子，包括持续因子 A22、尿嘧啶 DNA 糖基化酶 E4 和磷蛋白 H5。然而，这些病毒因子的分子作用尚不清楚。在这里，我们在不同的引物-模板 DNA 底物存在的情况下，对 F8-A22-E4 和 F8-A22-E4-H5 复合物的结构进行了表征。E4 位于模板单链 DNA（ssDNA）上 F8 的上游，具有催化活性，突出了 DNA 碱基切除修复和 DNA 合成之间的功能偶联。此外，H5 以四聚体的形式结合在 F8 下游的双链 DNA（dsDNA）区域，其位置与真核聚合酶复合物中的 PCNA（增殖细胞核抗原）相似。H5 的缺失或其 DNA 相互作用的破坏导致全长 DNA 产物的合成减少。这些结构为聚合酶的工作循环提供了快照，并深入了解这些在病毒 DNA 复制中必不可少的因子的机制。
