A light-driven proton pump in the distant relative

Researchers examined the group of microorganisms classified as Asgard archaea and found a protein in their membrane that functions as a light-activated miniature pump.

The schizorhodopsin protein pulls protons into the body of the organism.

This research could lead to new biomolecular tools to control the pH in cells or microorganisms, and possibly more. The Asgard archaeos are relatively new to science, but they are old and important to us in several ways.

They are unicellular organisms and were originally found on the sea floor.

Asgard archaea are so-called prokaryotes: they have no cell nucleus, yet they are genetically close to unicellular organisms, the eukaryotes, which contain a cell nucleus.

They are like a modern analogue of an old common ancestor, and the race to explore these small but significant organisms continues.

Associate Professor Keiichi Inoue from the Institute of Solid State Physics at Tokyo University, Professor Hideki Kandori from the Nagoya Institute of Technology, and her team decided to investigate a feature of the Asgard Archaea that is not unique to her, but is special in her case is interesting, namely photosensitive or photosensitive proteins called rhodopsins.

The organisms live on the bottom of oceans and lakes, so it is surprising that they need any kind of photosensitivity. ”We examined the molecular function of special rhodopsins in the Asgard archaeea, the schizorhodopsins, and found that they are microscopic, light-activated Pumps work, ”said Inoue.

Schizorhodopsin uses the energy of sunlight to take a proton into the cell along a path within the protein.

Many prokaryotes such as bacteria and other archaea use rhodopsins to pump out protons, but we find this newly characterized form particularly interesting in Asgard archaea. ”Since the scale on which this function occurs is nanoscopic, sophisticated measuring techniques with high sensitivity and … .

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