Crystal structure of the hemochromatosis protein HFE and characterization of its interaction with transferrin receptor.
HFE is an MHC-related protein that is mutated in the iron-overload disease hereditary hemochromatosis. HFE binds to transferrin receptor (TfR) and reduces its affinity for iron-loaded transferrin, implicating HFE in iron metabolism. The 2.6 A crystal structure of HFE reveals the locations of hemochromatosis mutations and a patch of histidines that could be involved in pH-dependent interactions. We also demonstrate that soluble TfR and HFE bind tightly at the basic pH of the cell surface, but not at the acidic pH of intracellular vesicles. TfR:HFE stoichiometry (2:1) differs from TfR:transferrin stoichiometry (2:2), implying a different mode of binding for HFE and transferrin to TfR, consistent with our demonstration that HFE, transferrin, and TfR form a ternary complex.
Pubmed ID: 9546397 RIS Download
Amino Acid Sequence | Binding Sites | Cell Membrane | Crystallography, X-Ray | HLA Antigens | Hemochromatosis | Hemochromatosis Protein | Histocompatibility Antigens Class I | Humans | Hydrogen-Ion Concentration | Kinetics | Membrane Proteins | Models, Molecular | Protein Structure, Secondary | Receptors, Transferrin