EXPLORING THE SPECIFICITY POCKETS OF 2 HOMOLOGOUS SH3 DOMAINS USING STRUCTURE-BASED, SPLIT-POOL SYNTHESIS AND AFFINITY-BASED SELECTION

Split-pool synthesis was used to prepare large numbers of spatially-se parated molecules and thereby to investigate the specificity pockets o f similar SH3 domains found in the tyrosine kinases Src and lick. By t aking into account the structure of the Src SH3 domain complexed to a ligand containing non-peptide-binding elements, the molecules were des igned to complement the topography of the protein's binding pocket. Th is procedure led to the discovery of ligands having greater affinity a nd enhanced selectivity for the Src SH3 domain. It also yielded non-na tural ligands that bind selectively to the Hck SH3 domain. Insights ga ined from this strategy may facilitate the discovery of molecules usef ul for evaluating the cellular function of SH3 domain-containing prote ins.