ABSTRACT
One of the principal modes of cell-cell communication, as well as control of biochemical processes in cells, relies upon proteins binding to a ligand. The ligand could be another protein, a nucleic acid, or a small molecule. Phage display is a tool that makes possible both presentation of large repertoires of naturally occurring proteins, and the derivation of protein ligands that have never previously been known to exist in nature. The very essence of phage display is that the displayed protein is encoded in the nucleic acid encapsulated by the phage particle, hence creating a physical coupling between genotype and phenotype [1]. Different protein sequences can be displayed by cloning the genes of interest as they occur in nature, or simply modifying the sequence of the DNA through molecular engineering. The simultaneous display of many different molecules on a population of phage then collectively makes what is called a phage library.
