Fig. (2) shows the distributions of the protein dimensions, measured by the number of amino acid residues, for the single-and multi-domain proteins examined in the CASP7 experiment. As expected, single-domain proteins tend to be smaller than multi-domain proteins, though some overlap between the two distributions exists. Fig. (2) . Distribution of the number of residues (nres) in the singleand muti-domain proteins examined in the CASP7 experiment.