synopsisA computational method for attempting to predict protein complexes from the CCF ordinates of the individual proteins has been developed. It is based on matching complementary patterns of knobs and holes. The computer algorithm correctly and uniquely predicts the association of the alpha and beta subunits to form the up dimer corresponding to the atPl interface in the hemoglobin tetramer. It fails to correctly dock trypsin inhibitor onto trypsin. Nevertheless, this lone success is still a significant advance over previous proteindocking algorithms. The method is also important because it introduces several ways to measure the shape of protein surface regions.