New Article in Nature Microbiology
An international research team, including scientists from the Algatech Centre of the Institute of Microbiology of the Czech Academy of Sciences, has described a new type of light-harvesting apparatus in marine archaea. A study published in the prestigious journal Nature Microbiology shows that these microorganisms use rhodopsins with additional carotenoid antennas to more efficiently capture light energy.
A study published in Nature Microbiology describes a previously unknown mechanism of light energy capture in marine archaea of the Asgard group. These microorganisms have attracted growing attention in recent years as probable direct ancestors of more complex eukaryotic organisms. Because members of the Asgard group cannot yet be cultivated in laboratory conditions, their study relies on the analysis of environmental DNA collected from marine habitats.
In the computer-assembled genomes of these organisms, scientists discovered genes encoding a new group of microbial rhodopsins—light-activated proteins that, upon illumination, transport protons across biological membranes and help generate ATP. Unlike visual rhodopsins (e.g. those found in the eyes of animals), the newly described rhodopsins contain additional light-harvesting antennas composed of hydroxylated carotenoids, such as lutein, diatoxanthin and fucoxanthin, which allow them to absorb blue light—common in ocean waters—more effectively.
The international team encompassed researchers from Israel, Japan, Germany, Switzerland and Czech Republic. Researchers from the Algatech Centre of the Institute of Microbiology CAS—Daniela Bárcenas-Pérez, José Cheel, and Michal Koblížek—prepared the purified carotenoids needed to reconstitute functional rhodopsins in the laboratory, enabling the team to clearly demonstrate their light-harvesting function. This discovery significantly broadens our understanding of the evolution of light-powered phototrophy in ocean-dwelling microorganisms.