Dynamics and mechanism of a light-driven chloride pump

How cells pump ions

30 September 2022

Key insights have been gleaned into the molecular mechanism by which single-celled algae and bacteria use light to import chloride ions from their environment.

The transport of chloride ions is a key process in biological systems, affecting many cell properties. Many single-celled algae and bacteria have light-driven pumps built into their cell membranes that enable them to convey chloride ions into their cells. But just how they use light to drive pumping and why transport only occurs in one direction has been unclear.

Now, by using powerful analytic techniques, a team led by researchers from the Paul Scherrer Institute in Switzerland has shed light on these aspects of chloride transport in a marine bacterium.

In particular, they discovered how chloride ions are attracted and bind to a protein in the pump and then how light causes the ions to move deeper into the protein. They also identified gates that prevent backflow of chloride ions.

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References

1. Science 375, 845–851 (2022). doi: 10.1126/science.abj6663