Structurally inherent antigenic sites. Localization of the antigenic sites of the alpha-chain of human haemoglobin in three host species by a comprehensive synthetic approach.

The antigenic structure of the alpha-chain of human haemoglobin was studied by a synthetic approach consisting of the synthesis of a series of consecutive overlapping peptides that together systematically represent the entire primary structure of the protein. This approach enabled the identification of a full profile of immunochemically active alpha-chain peptides and the localization of its major 'continuous' antigenic sites. Antibodies to haemoglobin raised in each of three different species (goat, rabbit and mouse) recognize similar sites on the alpha-chain. Further, the molecular locations of these sites coincide with alpha-chain regions extrapolated from antigenic sites of the conformationally similar myoglobin molecule. These findings support our earlier proposed concept of 'structurally inherent antigenic sites', namely that antigenicity is conferred on certain surface regions of proteins by virtue of their three-dimensional locations. Thus the antigenic sites of conformationally related proteins are likely to have similar molecular locations.