Possible three-dimensional backbone folding around antibody combining site of immunoglobulin MOPC167

Using a recently developed method of predicting possible three dimensional foldings of immunoglobulin backbones around antibody combining sites, we have attempted to construct the structure of immunoglobulin MOPC167 which could bind phosphorylcholine. A small pocket was present in the middle of the predicted structure similar to that of another phosphorylcholine binding immunoglobulin, McPC603, the tertiary structure of which has been determined by X-ray diffraction studies. Although detailed atomic co-ordinates of McPC603 were not available, a rough comparison between these structures strongly suggested that the foldings of complementarity determining regions were alike only for those with identical lengths and similar amino acid sequences. The predicted structure of MOPC167 as compared with the previously predicted structure of MOPC315, a 2,4-dinitrophenol binding immunoglobulin, further suggested that the light chain of one immunoglobulin could indeed combine with the heavy chain of another immunoglobulin, but might not result in a reasonable site for binding antigens.