The extreme halophile Halococcus morrhuae (ATCC^® 17082) contains a 108‐nucleotide insertion in its 5S rRNA. Large rRNA expansions in Archaea are rare. This one almost doubles the length of the 5S rRNA. In order to understand how such an insertion is accommodated in the ribosome, we obtained a cryo‐electron microscopy reconstruction of the native large subunit at subnanometer resolution. The insertion site forms a four‐way junction that fully preserves the canonical 5S rRNA structure. Moving away from the junction site, the inserted region is conformationally flexible and does not pack tightly against the large subunit. The high‐salt requirement of the H. morrhuae ribosomes for their stability conflicted with the low‐salt threshold for cryo‐electron microscopy procedures. Despite this obstacle, this is the first cryo‐electron microscopy map of Halococcus ribosomes.

中文翻译：

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极嗜盐古细菌 Halococcus morrhuae 的 5S 核糖体 RNA 中大量插入的冷冻电子显微镜可视化。

极端嗜盐菌Halococcus morrhuae (ATCC ^® 17082 ) 在其 5S rRNA 中包含 108 个核苷酸的插入。古生菌中的大型 rRNA 扩增很少见。这几乎是 5S rRNA 长度的两倍。为了了解这种插入是如何容纳在核糖体中的，我们以亚纳米分辨率获得了天然大亚基的低温电子显微镜重建。插入位点形成一个完全保留典型 5S rRNA 结构的四向连接。远离连接点，插入的区域在构象上是灵活的，不会紧紧地靠在大亚基上。河豚的高盐需求核糖体的稳定性与低温电子显微镜程序的低盐阈值相冲突。尽管存在这一障碍，但这是首张Halococcus核糖体的低温电子显微镜图。