Indexed on: 01 Jul '97Published on: 01 Jul '97Published in: Journal of protein chemistry
Phage display is a technique in which a foreign protein or peptide is presented at the surface of a (filamentous) bacteriophage. This system, developed by Smith [(1985), Science228, 1315–1317], was originally used to create large libraries of antibodies for the purpose of selecting those that strongly bound a particular antigen. More recently it was also employed to present peptides, domains of proteins, or intact proteins at the surface of phages, again to identify high-affinity interactions with ligands. Here we want to illustrate the use of phage display, in combination with PCR saturation mutagenesis, for the study of protein–protein interactions. Rather than selecting for mutants having high affinity, we systematically investigate the binding of every variant with its natural ligand. Via a modified ELISA we can calculate a relative affinity. As a model system we chose to display thymosin β4 on the phage surface in order to study its interaction with actin.