Display of peptides and proteins on the surface of bacteriophage lambda

The display of peptides or proteins on the surface of viruses is an important technology for studying peptides or proteins and their interaction with other molecules. Here we describe a display vehicle based on bacteriophage lambda that incorporates a number of features distinct from other currently used display systems. Fusions of peptides or protein domains have been made to the amino terminus of the 11-kDa D protein of the lambda capsid. These fusions assemble onto the viral capsid and appear to be accessible to ligand interactions, based on the ability of a monoclonal antibody to recognize an epitope fused to the D protein on phage heads. To produce large D fusion display libraries and yet avoid the cumbersome task of cloning many fragments into lambda DNA, we have used the Cre-loxP site-specific recombination system in vivo to incorporate plasmids encoding the D fusions into the phage genome. Finally, we show that D fusion proteins can be added in vitro to phage lacking D protein and be assembled onto the viral capsid.