Multipurpose vectors for peptide expression on the M13 viral surface.

We have developed a set of three cloning vectors for the expression of polypeptides on the surface of the M13 viral coat. The M13mp8 genome has been engineered for expression of foreign protein sequences near the NH2-terminus of the mature pIII protein, which is present in five copies on the outside of each M13 viral particle. All three of the vectors carry the same two useful restriction sites for directed cloning of inserts in the pIII coding region; in addition, one vector carries the bacterial gene conferring resistance to the antibiotic tetracycline, and another expresses the lacZ' polypeptide that allows functional complementation of beta-galactosidase activity within the host bacterial cell. All of these vectors propagate well in E. coli DH5 alpha F' cells and do not require helper phage. We demonstrate that a bacteriophage, expressing an eleven amino acid epitope (from human c-myc) at the NH2-terminus of pIII in one of our vectors, can be purified from a vast mixture of other M13 phage through panning techniques. In particular, we find that the c-myc-expressing viral particles can be easily recovered from phage mixtures with the biotinylated form of the monoclonal antibody, 9E10, and streptavidin-coated MagneSphere beads.