Abstract 2904 Substrate selectivity in Nramp-family metal ion transporters

We investigate membrane transporters from the Nramp (Natural Resistance-Associated Macrophage Protein) family, which play crucial roles in transition metal ion homeostasis. Nramps are found across the tree of life and belong to the large LeuT-fold transporter superfamily. Nramps selectively import rare divalent transition metal ions, like Mn2+ and Fe2+, into the cytosol while excluding alkaline earth metals like Mg2+ and Ca2+. Our high-resolution crystal structures of Deinococcus radiodurans (Dra)Nramp highlight three main stable conformations supporting an alternating-access transport cycle and distinct Mn2+ coordination geometries in each conformation.