DATE2025.05.29 #Press Releases

Discovery of a Highly Sensitive Light-Driven Hydrogen Ion Pump from Prometheus Archaea

-- A New Form of Light Utilization by Archaea Involved in the Emergence of Eukaryotes --

Summary

A research group led by Associate Professor Keiichi Inoue and Project Researcher Masae Konno of the Institute for Solid State Physics at the University of Tokyo, together with Professor Osamu Nureki and Assistant Professor Wataru Shihoya (at the time of research; currently Associate Professor at Keio University), Project Assistant Professor Tatsuki Tanaka, graduate students Yuma Matsuzaki and Shunya Murakoshi from the Graduate School of Science, the University of Tokyo, as well as Distinguished Professor Hideki Kandori, Associate Professor Kodai Katayama, Researcher Rei Yoshizumi, and graduate students Shota Itakura (at the time of research) and Yosuke Mizuno from Nagoya Institute of Technology, have revealed that Heimdallarchaeota — a group of archaea considered to be among the closest living relatives of the last common ancestor of eukaryotes — possess a protein called “Heimdallrhodopsin.” This protein uses carotenoid pigments to efficiently capture solar energy, which is then used to transport protons (H⁺) and convert the energy into chemical energy.

Using advanced laser-based spectroscopic techniques, the team demonstrated for the first time that the carotenoid pigments in Heimdallrhodopsin act as light-harvesting antennas and contribute to H⁺ transport. Furthermore, X-ray crystallographic analysis revealed that the protein has a unique structure optimized for binding various carotenoid pigments. Until now, it was entirely unknown that Heimdallarchaeota could efficiently harness light to support their growth. This discovery sheds new light on a previously unexplored aspect of this organism and holds significant academic value in understanding the evolution of life.

Moreover, since Heimdallrhodopsin utilizes carotenoids such as lutein—which are also found in the human body—this protein is expected to serve as a novel biomolecular tool in the future, potentially contributing to the development of high-sensitivity vision restoration technologies and light-based therapies for neurological disorders.

This research was published online in the May 29 edition of the British scientific journalNature Microbiology.

Figure: Rhodopsin of Heimdallarchaeota captures light with high sensitivity using carotenoid pigments

Links

Institute for Solid State Physics, The University of Tokyo; Nagoya Institute of Technology; Japan Science and Technology Agency (JST)

Journal

Journal Name	Nature Microbiology
Title of paper	Light-harvesting by antenna-containing rhodopsins in pelagic Asgard archaea