IDENTIFICATION OF SPECIFICITY-DETERMINING RESIDUES IN ANTIBODIES

The successful identification of the residues that contact ligand has important implications, especially in view of the increasing use of an tibodies in various medical and industrial applications. Analysis of t he crystallographically derived, three-dimensional Structures of five antibody-antigen complexes and of the available amino acid sequence da ta on antibody variable regions reveals that the residues that contact antigen are in the main also the most variable. It is proposed that a good first guess of the identity of the specificity-determining resid ues can be made from an examination of the variability values at seque nce positions. New boundaries for the complementarity-determining regi ons are proposed.