mRNA display-based selections using synthetic peptide and natural protein libraries.

mRNA display is a powerful in vitro selection technique that can be applied toward the identification of peptides or proteins with desired properties. The physical conjugation between a protein and its own RNA presents unique challenges in manipulating the displayed proteins in an RNase-free environment. This protocol outlines the generation of synthetic peptide and natural proteome libraries as well as the steps required for generation of mRNA-protein fusion libraries, in vitro selection, and regeneration of the selected sequences. The selection procedures for the identification of Ca(2+)-dependent, calmodulin-binding proteins from synthetic peptide and natural proteome libraries are presented.