American Association for the Advancement of Science (AAAS) Acta Medica Okayama 2375-2548 8 12 2022 Structure and dynamics of Odinarchaeota tubulin and the implications for eukaryotic microtubule evolution eabm2225 EN Caner Akıl Research Institute for Interdisciplinary Science, Okayama University Samson Ali Research Institute for Interdisciplinary Science, Okayama University Linh T. Tran Research Institute for Interdisciplinary Science, Okayama University Jérémie Gaillard University of Grenoble-Alpes, CEA, CNRS, INRA, Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, CytoMorpho Lab Wenfei Li National Laboratory of Solid State Microstructure, Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University Kenichi Hayashida Cellular and Structural Physiology Institute (CeSPI), Nagoya University Mika Hirose Institute for Protein Research, Osaka University Takayuki Kato Institute for Protein Research, Osaka University Atsunori Oshima Cellular and Structural Physiology Institute (CeSPI), Nagoya University Kosuke Fujishima Tokyo Institute of Technology, Earth-Life Science Institute (ELSI) Laurent Blanchoin University of Grenoble-Alpes, CEA, CNRS, INRA, Interdisciplinary Research Institute of Grenoble, Laboratoire de Physiologie Cellulaire & Végétale, CytoMorpho Lab Akihiro Narita Division of Biological Science, Graduate School of Science, Nagoya University Robert C. Robinson Research Institute for Interdisciplinary Science, Okayama University Tubulins are critical for the internal organization of eukaryotic cells, and understanding their emergence is an important question in eukaryogenesis. Asgard archaea are the closest known prokaryotic relatives to eukaryotes. Here, we elucidated the apo and nucleotide-bound x-ray structures of an Asgard tubulin from hydrothermal living Odinarchaeota (OdinTubulin). The guanosine 5��-triphosphate (GTP)–bound structure resembles a microtubule protofilament, with GTP bound between subunits, coordinating the �g+�h end subunit through a network of water molecules and unexpectedly by two cations. A water molecule is located suitable for GTP hydrolysis. Time course crystallography and electron microscopy revealed conformational changes on GTP hydrolysis. OdinTubulin forms tubules at high temperatures, with short curved protofilaments coiling around the tubule circumference, more similar to FtsZ, rather than running parallel to its length, as in microtubules. Thus, OdinTubulin represents an evolutionary stage intermediate between prokaryotic FtsZ and eukaryotic microtubule-forming tubulins. No potential conflict of interest relevant to this article was reported.