Optimization of the process of inverted peptides (PIPE^PLUS) to screen PDZ domain ligands

PDZ domains play crucial roles in cell signaling processes and are therefore attractive targets for the development of therapeutic inhibitors. In many cases, C-terminal peptides are the physiological binding partners of PDZ domains. To identify both native ligands and potential inhibitors we have screened arrays synthesized by the process of inverted peptides (PIPE), a variant of SPOT synthesis that generates peptides with free C-termini. Here, we present the development of a new functionalized cellulose membrane as solid support along with the optimized PIPE^PLUS technology. Improved resolution and accuracy of the synthesis were shown with peptide arrays containing both natural and non-natural amino acids. These new screening possibilities will advance the development of active, selective and metabolically stable PDZ interactors.