Solid-phase peptide synthesis as an enabling tool for proteomics

Proteomics and other approaches to systems biology can benefit significantly from new solid-phase chemical tools, especially new methods for affinity pull-clown of proteins from complex mixtures. Here we describe a novel chemical methodology for proteomics in which phosphopeptides are assembled by solid-phase synthesis on beads which are compatible with subsequent affinity pull-down of phosphopeptide-binding proteins. Support-bound phosphopeptides were synthesized directly on PEGA solid supports through a BAL-type handle. The phosphopeptides were constructed around the Bad Ser 136 and Ser 112 phosphorylation motives and were able to pull-clown both transfected and endogenous 14-3-3 proteins from cell lysates. This method for synthesis and display of phosphopeptides on-bead is likely to have wide applicability for proteomics.