Identification of small molecule binding molecules by affinity purification using a specific ligand immobilized on PEGA resin.

We investigated the application of resins used in solid-phase synthesis for affinity purification. A synthetic ligand for FK506-binding protein 12 (SLF) was immobilized on various resins, and the binding assays between the SLF-immobilized resins and FK506-binding protein 12 (FKBP12) were performed. Of the resins tested in this study, PEGA resin was the most effective for isolating FKBP12. This matrix enabled the isolation of FKBP12 from a cell lysate, and the identification of SLF-binding peptides from a phage cDNA library. We confirmed the interaction between SLF and these peptides using a cuvette type quartz crystal microbalance (QCM) apparatus. Our study suggests that PEGA resin has great potential as a tool not only for the purification and identification of small-molecule binding proteins but also for the selection of peptides that recognize target molecules.