A Light Driven Proton Pump in Distant Relative of Single-Celled Organisms
Arthur T Knackerbracket has found the following story:
Asgard archaea are relatively new to science, but they are ancient and important to us in more ways than one. They are single-celled organisms and were originally found at the bottom of the ocean. Asgard archaea are what are known as a prokaryote, they do not have a cell nucleus, yet despite this, they are genetically close to single-celled organisms called eukaryotes which do contain a cell nucleus. They are like a modern analogue of an ancient common ancestor.
[...] Associate Professor Keiichi Inoue from the Institute for Solid State Physics at the University of Tokyo, Professor Hideki Kandori from Nagoya Institute of Technology and their team chose to study a feature of Asgard archaea that although not unique to them, is especially interesting in their case, and that is light-sensitive or photoreceptive proteins called rhodopsins. The organisms live at the bottom of oceans and lakes so it's surprising they need any kind of sensitivity to light.
"We explored the molecular function of special rhodopsins in Asgard archaea called schizorhodopsins and found that they acted as light-activated microscopic pumps," explained Inoue. "Schizorhodopsin uses sunlight energy to take up a proton into the cell along a pathway inside the protein. Many prokaryotes such as bacteria and other archaea use rhodopsins to pump protons out, but we find this newly characterized form in Asgard archaea particularly interesting."
[...] "These findings will help us better understand proton and other ion transport mechanisms. In addition, schizorhodopsin could be made into a useful molecular tool for researchers," commented Inoue. "For example in optogenetics, which is a new methodology to control various cellular phenomena with light. Schizorhodopsins could also be used to control the pH inside cells or microorganisms with light, as pH can be altered by changing the proton concentration."
Journal Reference: "Schizorhodopsins: A novel family of rhodopsins from Asgard archaea that function as light-driven inward H+ pumps" Science Advances (2020). DOI: 10.1126/sciadv.aaz2441 , https://advances.sciencemag.org/content/6/15/eaaz2441
Also at Science Daily and phys.org.
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