Jarrell Ken F, Albers Sonja-Verena, Machado J Nuno de Sousa
Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada.
Institute for Biology II- Microbiology, Molecular Biology of Archaea, University of Freiburg, Schänzlestraße 1, Freiburg 79104, Germany.
FEMS Microbes. 2021 Apr 8;2:xtab002. doi: 10.1093/femsmc/xtab002. eCollection 2021.
Each of the three Domains of life, Eukarya, Bacteria and Archaea, have swimming structures that were all originally called flagella, despite the fact that none were evolutionarily related to either of the other two. Surprisingly, this was true even in the two prokaryotic Domains of Bacteria and Archaea. Beginning in the 1980s, evidence gradually accumulated that convincingly demonstrated that the motility organelle in Archaea was unrelated to that found in Bacteria, but surprisingly shared significant similarities to type IV pili. This information culminated in the proposal, in 2012, that the 'archaeal flagellum' be assigned a new name, the archaellum. In this review, we provide a historical overview on archaella and motility research in Archaea, beginning with the first simple observations of motile extreme halophilic archaea a century ago up to state-of-the-art cryo-tomography of the archaellum motor complex and filament observed today. In addition to structural and biochemical data which revealed the archaellum to be a type IV pilus-like structure repurposed as a rotating nanomachine (Beeby . 2020), we also review the initial discoveries and subsequent advances using a wide variety of approaches to reveal: complex regulatory events that lead to the assembly of the archaellum filaments (archaellation); the roles of the various archaellum proteins; key post-translational modifications of the archaellum structural subunits; evolutionary relationships; functions of archaella other than motility and the biotechnological potential of this fascinating structure. The progress made in understanding the structure and assembly of the archaellum is highlighted by comparing early models to what is known today.
生命的三个域，即真核生物域、细菌域和古菌域，都有用于游动的结构，这些结构最初都被称为鞭毛，尽管事实上它们在进化上与其他两个域中的任何一个都没有关系。令人惊讶的是，即使在细菌和古菌这两个原核生物域中也是如此。从20世纪80年代开始，证据逐渐积累，令人信服地表明古菌中的运动细胞器与细菌中的不同，但令人惊讶的是，它与IV型菌毛有显著的相似之处。这些信息最终促成了在2012年提出将“古菌鞭毛”赋予一个新名称——古菌菌毛。在这篇综述中，我们提供了关于古菌菌毛和古菌运动研究的历史概述，从一个世纪前对运动性嗜盐古菌的首次简单观察开始，直至如今对古菌菌毛运动复合体和丝状体的先进冷冻断层扫描研究。除了结构和生化数据揭示古菌菌毛是一种重新用作旋转纳米机器的IV型菌毛样结构（Beeby等人，2020年）之外，我们还综述了最初的发现以及随后使用多种方法取得的进展，以揭示：导致古菌菌毛丝状体组装的复杂调控事件（菌毛形成）；各种古菌菌毛蛋白的作用；古菌菌毛结构亚基的关键翻译后修饰；进化关系；除运动之外古菌菌毛的功能以及这种迷人结构的生物技术潜力。通过将早期模型与当今所知内容进行比较，突出了在理解古菌菌毛的结构和组装方面所取得的进展。
