Discovery of ligands for beta gamma subunits from phage-displayed peptide libraries.

We have described a method using polyvalent peptide display on filamentous phage that can be used to identify ligands that bind to G protein beta gamma subunits. Also described is how to construct phage that have known beta gamma binding sequences fused to the coat protein to allow a competition analysis to be performed. Once selected or constructed, these phage-bearing beta gamma-binding peptides are powerful tools for mapping interaction sites for beta gamma binding proteins and can be used to begin to dissect the unique modes of binding for individual beta gamma subunit-regulated effectors.