Baculovirus is the most studied insect virus owing to a broad ecological distribution and ease of engineering for biotechnological applications. However, its structure and evolutionary place in the virosphere remain enigmatic. Using cryo–electron microscopy, we show that the nucleocapsid forms a covalently cross-linked helical tube protecting a highly compacted 134-kilobase pair DNA genome. The ends of the tube are sealed by the base and cap substructures, which share a 126-subunit hub but differ in components that promote actin tail–mediated propulsion and nuclear entry of the nucleocapsid, respectively. Unexpectedly, sensitive searches for hidden evolutionary links show that the morphogenetic machinery and conserved oral infectivity factors originated within the lineage of baculo-like viruses (class Naldaviricetes ). The unique viral architecture and structural atlas of hallmark proteins firmly place these viruses into a separate new realm, the highest taxonomy rank, and provide a structural framework to expand their use as sustainable bioinsecticides and biomedical tools.

中文翻译：

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原型杆状病毒的核衣壳结构和结构图谱定义了新病毒领域的标志


杆状病毒是研究最多的昆虫病毒，因为它具有广泛的生态分布和易于生物技术应用的工程设计。然而，它在病毒圈中的结构和进化位置仍然是个谜。使用冷冻电子显微镜，我们表明核衣壳形成共价交联螺旋管，保护高度紧凑的 134 kb 对 DNA 基因组。管的末端由底座和帽子结构密封，它们共享一个 126 个亚基枢纽，但分别在促进肌动蛋白尾部介导的推进和核衣壳核进入的成分上有所不同。出乎意料的是，对隐藏的进化联系的敏感搜索表明，形态发生机制和保守的口腔感染因子起源于杆状病毒（Naldaviricetes 类）的谱系。独特的病毒结构和标志性蛋白的结构图谱将这些病毒牢牢地置于一个单独的新领域，即最高分类学等级，并提供了一个结构框架，以扩大它们作为可持续生物杀虫剂和生物医学工具的使用。