Giant viruses (Nucleocytoviricota) have a largely conserved lifecycle, yet how they cram their large genomes into viral capsids is mostly unknown. The major capsid protein and the packaging ATPase (pATPase) comprise a highly conserved morphogenesis module in giant viruses, yet some giant viruses dispense with an icosahedral capsid, and others encode multiple versions of pATPases, including conjoined ATPase doublets, or encode none. Some giant viruses have acquired DNA-condensing proteins to compact their genomes, including sheath-like structures encasing folded DNA or densely packed viral nucleosomes that show a resemblance to eukaryotic nucleosomes at the telomeres. Here, we review what is known and unknown about these ATPases and condensing proteins, and place these variations in the context of viral lifecycles.

巨型病毒（核细胞病毒）的生命周期在很大程度上是保守的，但它们如何将大型基因组塞进病毒衣壳中却大多未知。主要衣壳蛋白和包装 ATP 酶 (pATPase) 构成巨型病毒中高度保守的形态发生模块，但一些巨型病毒没有二十面体衣壳，而其他病毒则编码多个版本的 pATP 酶，包括连体 ATP 酶双联体，或不编码。一些巨型病毒已经获得了 DNA 压缩蛋白来压缩其基因组，包括包裹折叠 DNA 的鞘状结构或密集堆积的病毒核小体，其端粒处与真核核小体相似。在这里，我们回顾了这些 ATP 酶和浓缩蛋白的已知和未知内容，并将这些变化置于病毒生命周期的背景下。