Patent ID: 7790405

Claim:
A method for identifying a polypeptide which binds to a preselected epitope of a target protein, which comprises: a) providing a library of phage particles that express polypeptides on the surface of the phage particles; b) preparing a decoy protein which has about 5-10 changes in the amino acid sequences within about a 5-15 linear segment of the target protein corresponding to the preselected epitope of the target protein; c) incubating the library of phage particles with the target protein to select phage particles with polypeptides that bind to the target protein; d) adding the decoy protein as a competitor in molar excess concentration to negatively select for phage particles specific for the preselected epitope; e) separating the phage particles that bind to the target protein from those that bind to the decoy protein and f) recovering the phage particles bound to the target protein.