Abstract Viruses infecting hyperthermophilic archaea represent one of the most enigmatic parts of the global virome, with viruses from different families showing no genomic relatedness to each other or to viruses of bacteria and eukaryotes. Tristromaviruses, which build enveloped filamentous virions and infect hyperthermophilic neutrophiles of the order Thermoproteales, represent one such enigmatic virus families. They do not share genes with viruses from other families and have been believed to represent an evolutionarily independent virus lineage. A cryo-electron microscopic reconstruction of the tristromavirus Pyrobaculum filamentous virus 2 at 3.4 Å resolution shows that the virion is constructed from two paralogous major capsid proteins (MCP) which transform the linear dsDNA genome of the virus into A-form by tightly wrapping around it. Unexpectedly, the two MCP are homologous to the capsid proteins of other filamentous archaeal viruses, uncovering a deep evolutionary relationship within the archaeal virosphere.

中文翻译：

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丝状病毒的结构揭示了古细菌病毒圈内的家族联系

摘要 感染超嗜热古细菌的病毒是全球病毒组中最神秘的部分之一，来自不同家族的病毒彼此之间或与细菌和真核生物的病毒没有基因组相关性。Tristromaviruses 构建有包膜的丝状病毒体并感染 Thermoproteales 的嗜热嗜中性粒细胞，代表了一个这样的神秘病毒家族。它们不与来自其他家族的病毒共享基因，并且被认为代表了一个进化独立的病毒谱系。以 3.4 Å 分辨率对三基质病毒 Pyrobaculum 丝状病毒 2 进行的冷冻电子显微镜重建表明，该病毒粒子是由两种旁系同源的主要衣壳蛋白 (MCP) 构建的，MCP 将病毒的线性 dsDNA 基因组通过紧紧包裹在病毒周围而转化为 A 型.