Pichia surface display: a tool for screening single domain antibodies.

Yeast surface display is being employed as an efficient tool for the isolation and engineering of traditional antibody fragments, both scFv and Fab, as well as single domain antibodies. Here we describe the protocols for a yeast surface display system developed in the methylothrophic yeast Pichia pastoris, the most commonly used yeast species for protein production. In this system the immune or maturated library of single domain antibodies is fused to the C-terminal domain of Saccharomyces cerevisiae alpha-agglutinin gene (SAG1) and expressed on the surface of P. pastoris cells. Labeling with ligands enables rapid and quantitative analysis in conjunction with isolation of single domain antibodies with the desired characteristics.