African swine fever virus (ASFV) is one of the most important causative agents of animal diseases and can cause highly fatal diseases in swine. ASFV DNA polymerase (DNAPol) is responsible for genome replication and highly conserved in all viral genotypes showing an ideal target for drug development. Here, we systematically determined the structures of ASFV DNAPol in apo, replicating and editing states. Structural analysis revealed that ASFV DNAPol had a classical right-handed structure and showed the highest similarity to the structure of human polymerase delta. Intriguingly, ASFV DNAPol has a much longer fingers subdomain, and the thumb and palm subdomain form a unique interaction that has never been seen. Mutagenesis work revealed that the loss of this unique interaction decreased the enzymatic activity. We also found that the β-hairpin of ASFV DNAPol is located below the template strand in the editing state, which is different from the editing structures of other known B family DNAPols with the β-hairpin above the template strand. It suggests that B family DNAPols have evolved two ways to facilitate the dsDNA unwinding during the transition from replicating into editing state. These findings figured out the working mechanism of ASFV DNAPol and will provide a critical structural basis for the development of antiviral drugs.

中文翻译：

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非洲猪瘟病毒 DNA 聚合酶的冷冻电镜结构


非洲猪瘟病毒 （ASFV） 是动物疾病最重要的病原体之一，可导致猪患上高度致命的疾病。ASFV DNA 聚合酶 （DNAPol） 负责基因组复制，在所有病毒基因型中高度保守，是药物开发的理想靶标。在这里，我们系统地确定了 apo 、复制和编辑状态下 ASFV DNAPol 的结构。结构分析显示 ASFV DNAPol 具有经典的右旋结构，与人聚合酶 delta 的结构相似性最高。有趣的是，ASFV DNAPol 有一个更长的手指亚结构域，拇指和手掌亚结构域形成了一种从未见过的独特相互作用。诱变工作表明，这种独特相互作用的丧失降低了酶活性。我们还发现，ASFV DNAPol 的 β 发夹在编辑状态下位于模板链下方，这与其他已知的 B 家族 DNAPol 的编辑结构不同，β发夹位于模板链上方。它表明 B 家族 DNAPol 已经进化出两种方式来促进 dsDNA 在从复制状态过渡到编辑状态期间的解旋。这些发现阐明了 ASFV DNAPol 的工作原理，将为抗病毒药物的开发提供关键的结构基础。