A 3-dimensional model building by homology of the HFE protein: molecular consequences and application to antibody development.

Genetic hemochromatosis (GH) is a common inherited disease of iron metabolism affecting 2-5 in 1000 individuals of European origin. A candidate gene for GH, namely HFE has been recently characterized. Structural studies of the protein product of the HFE gene are of major interest for a better understanding of the molecular physiopathology in iron overload. We have built a 3-dimensional model of the HFE protein based on congruent with40% homology of sequence identity with HLA-Aw68, another MHC class I molecule. This work presents the first 3-dimensional structure of HFE available in the public domain (http://swift.embl-heidelberg.de/service/francois). The 3-dimensional characteristics of the protein complexed with the beta2-microglobulin are presented. The model has been used to predict immunogenic loops and to develop an antibody able to recognize a protein exhibiting the same molecular weight as HFE. Structural consequences of two common mutations are debated and evolutionary hypotheses are considered in the discussion of the particular biological activity of HFE. This study shows that a strategy based on homology modeling is sufficient to undertake biological investigations.