A GENERAL-ROUTE TO FINGERPRINT ANALYSES OF PEPTIDE-ANTIBODY INTERACTIONS USING A CLUSTERED AMINO-ACID PEPTIDE LIBRARY - COMPARISON WITH A PHAGE DISPLAY LIBRARY

We provide a general route to fingerprint analyses of peptide-antibody interactions using a novel chemically synthesized peptide library. A combinatorial clustered amino acid peptide library XO(1)O(2)O(3)O(4)X (O = one of six amino acid clusters [APG], [DE], [HKR], [NQST], [FYW] and [ILVM]; X = randomized position) bound to a continuous cellulose m embrane support was designed to overcome the problem of combinatorial explosion in the synthesis of peptide libraries. This library served a s the starting point for the identification and detailed characterizat ion of a TGF alpha peptide epitope recognized by the antibody Tab2. By analysing 1728 hexapeptide mixtures and 1600 single hexapeptides we i dentified a large number of structurally different high affinity Tab2 binding molecules. Our data provide a detailed picture of the structur al basis of this antibody-peptide interaction. In addition to the dete ction of key amino acids involved in Tab2 binding we observed a high v ariability of Tab2 binding sequences supporting an induced fit mechani sm in antibody-peptide recognition. In contrast, a phage display hexap eptide library led to the detection of only one dominant Tab2 binding peptide. The data obtained also demonstrate the influence of phage pro teins on the interaction between the antibody and the displayed peptid e. Comparing both approaches with regard to ease of handling and ident ified sequences, the chemical libraries are clearly favored to study a ntibody-peptide interactions.