Generating a Platform for Fos Peptide Display on the pIX Coat Protein of the M13 Bacteriophage

The process of phage display utilizes manipulation of the bacteriophage genome to facilitate the presentation of novel peptides on the exterior of the phage particle as fusions to specific coat proteins. The best-characterized and most commonly employed forms of phage display involve the either the pIII or pVIII coat proteins of the M13 bacteriophage. In relation to the long, rod-shaped, filamentous M13 particle, three to five copies of the pIII protein are located exclusively at one end, whereas approximately 2,700 copies of pVIII coat the length of each particle. Here I report the construction and use of a plasmid in Escherichia coli directing the display of half of the Fos-Jun coiled-coil leucine zipper, Fos, on the lesser-studied pIX coat protein. The resulting Fos-pIX fusion protein is then displayed on the end of the M13 particle opposite pIII. Concurrently, this plasmid also directs the display of the other peptide half of the Fos-Jun heterodimer, Jun, on pIII, theoretically allowing Fos-Jun heterodimer formation to link M13 phage together end-to-end into self-assembling nanostructures. Phage display has been effectively used in a broad range of exciting applications from lithium-ion batteries to the generation of artificial antibodies to protein-targeted cancer nanomedicines, however, developing pIX as an alternative display platform offers potential complements to current pIII and pVIII display technology