The Archaea-and their viruses-remain the most enigmatic of life's three domains. Once thought to inhabit only extreme environments, archaea are now known to inhabit diverse environments. Even though the first archaeal virus was described over 40 years ago, only 117 archaeal viruses have been discovered to date. Despite this small number, these viruses have painted a portrait of enormous morphological and genetic diversity. For example, research centered around the various steps of the archaeal virus life cycle has led to the discovery of unique mechanisms employed by archaeal viruses during replication, maturation, and virion release. In many instances, archaeal virus proteins display very low levels of sequence homology to other proteins listed in the public database, and therefore, structural characterization of these proteins has played an integral role in functional assignment. These structural studies have not only provided insights into structure-function relationships but have also identified links between viruses across all three domains of life.

中文翻译：

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古细菌病毒：多样性，复制和结构。

古细菌及其病毒仍然是生命中三个领域中最神秘的部分。曾经被认为仅栖息于极端环境中的古细菌现在被认为栖息于多种环境中。尽管40年前就描述了第一种古细菌病毒，但迄今为止仅发现了117种古细菌病毒。尽管数量很少，但这些病毒仍描绘出巨大的形态和遗传多样性。例如，围绕古细菌生命周期各个步骤的研究导致发现了古细菌在复制，成熟和病毒体释放过程中采用的独特机制。在许多情况下，古细菌病毒蛋白质与公共数据库中列出的其他蛋白质相比，序列同源性非常低，因此，这些蛋白质的结构表征在功能分配中起着不可或缺的作用。这些结构研究不仅提供了对结构-功能关系的见解，而且还确定了生命所有三个领域之间的病毒之间的联系。