Sivabalasarma Shamphavi, Taib Najwa, Mollat Clara L, Joest Marie, Steimle Stefan, Gribaldo Simonetta, Albers Sonja-Verena
Faculty of Biology, Molecular Biology of Archaea, University of Freiburg, Freiburg, Germany.
Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany.
Nat Microbiol. 2025 Sep 17. doi: 10.1038/s41564-025-02110-8.
Motility in Archaea is driven by the archaellum, a rotary ATP-driven machinery unrelated to the bacterial flagellum. To date, archaella have been described exclusively in archaea; however, recent work reported archaellum genes in bacterial strains of the SAR202 clade (Chloroflexota). Here, using MacSyFinder, we show that bona fide archaellum gene clusters are widespread in several members of the Chloroflexota. Analysis of archaellum-encoding loci and Alphafold3-predicted structures show similarity to the archaellum machinery. Using cryo electron microscopy single-particle analysis, we solved the structure of the bacterial archaellum from Litorilinea aerophila to 2.7 Å. We also show the expression and assembly of this machinery in bacteria and its function in swimming motility. Finally, a phylogenomic analysis revealed two horizontal gene transfer events from euryarchaeal members to Chloroflexota. In summary, our study shows that a functional and assembled archaellum machinery can be exchanged between the two prokaryotic domains.
古菌的运动由古菌鞭毛驱动，这是一种由ATP驱动的旋转机器，与细菌鞭毛无关。迄今为止，仅在古菌中描述过古菌鞭毛；然而，最近的研究报道了SAR202进化枝（绿弯菌门）的细菌菌株中存在古菌鞭毛基因。在这里，我们使用MacSyFinder表明，真正的古菌鞭毛基因簇广泛存在于绿弯菌门的几个成员中。对编码古菌鞭毛的基因座和Alphafold3预测结构的分析显示与古菌鞭毛机器相似。使用冷冻电子显微镜单颗粒分析，我们将嗜水气单胞菌的细菌古菌鞭毛结构解析到了2.7埃。我们还展示了这种机器在细菌中的表达和组装及其在游动运动中的功能。最后，系统基因组分析揭示了从古菌成员到绿弯菌门的两次水平基因转移事件。总之，我们的研究表明，功能性和组装好的古菌鞭毛机器可以在两个原核域之间交换。
