Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have determined the atomic-level structure of a zinc-transporter protein, a molecular machine that regulates levels of this crucial trace metal micronutrient inside cells. As described in a paper just published in Nature Communications, the structure reveals how the cellular membrane protein shifts its shape to move zinc from the environment into a cell, and temporarily blocks this action automatically when zinc levels inside the cell get too high.
“Zinc is important for many biological activities, but too much can be a problem,” said Qun Liu, the Brookhaven Lab biophysicist who led the project. “During evolution, different organisms have evolved in many ways to regulate zinc. But no one has shown that a transporter that controls the uptake of zinc from the environment can regulate its own activity. Our study is the first to show a zinc transporter with such a built-in sensor.”
The research was conducted as part of Brookhaven Lab’s Quantitative Plant Sciences Initiative (QPSI). Using a bacterial version of a zinc transporter that shares essential features with zinc transporters in plants, the scientists gained key insights into how these proteins work.
“This research is part of our effort to understand how micronutrients like zinc are taken up by plants so we can understand how to design plants that are better able to grow on marginal land for the production of bioenergy,” said Brookhaven Lab Biology Department Chair John Shanklin, a co-author on the paper.