2.A.89.1.2
The vacuolar Fe²⁺ uptake transporter, VIT1 of 250 aas and 5 putative TMSs (Gollhofer et al. 2011). The crystal structure of the orthogous VIT1 from rose gum, Eucalyptus grandis, which probably functions as a H⁺-dependent antiporter for Fe²⁺ and other transition metal ions, has been solved. VIT1 adopts a novel protein fold forming a dimer of five membrane-spanning domains, with an ion-translocating pathway constituted by the conserved methionine and carboxylate residues at the dimer interface. The second transmembrane helix protrudes from the lipid membrane by about 40 Å, and connects to a three-helical bundle, triangular, cytoplasmic domain, which binds to the substrate metal ions in preparation for their transport (Kato et al. 2019).