METHODS FOR THE CHEMICAL SYNTHESIS AND READOUT OF SELF-ENCODED ARRAYSOF POLYPEPTIDE ANALOGS

The synthesis of defined arrays of polypeptide analogues in conjunctio n with a simple self-encoded chemical readout system provides a powerf ul method for the systematic investigation of the relationship between polypeptide molecular structure and function. A novel solid-phase syn thesis procedure was used to prepare arrays of polypeptide analogues i n which a specific modification was systematically incorporated into a unique position in a peptide sequence; The synthesis was carried out in such a way that the resulting arrays contained a defined family of modified peptides, with each peptide molecule containing only a single specific modification. The array of polypeptide analogues was self-en coded in a positional fashion by incorporating a selectively cleavable bond into the analogue structure. Following cleavage of the polypepti de analogue array, analysis of the resulting peptide fragments by MALD I mass spectrometry defined, in a single step, the presence and identi ty of each peptide analogue in the mixture. The feasibility of this ap proach was demonstrated by the synthesis and mass spectrometric readou t of an array of nine analogues of the 58-residue polypeptide chain of the cCrk N-terminal SH3 domain, before and after folding and affinity selection.