A number of small proteins are being used as scaffolds for the display
and selection of novel peptides for use as potential biotherapeutics.
Transferrin is an ideal protein for engineering novel non-antibody
scaffold protein binders (Trans-bodies(tm)). Transferrin has free N- and
C- termini and several flexible surface regions that allow fusion and/or
insertion of biologically active peptides. Several such proteins based
on natural peptides have shown high level production in yeast and long
half-life in vivo. We have developed a novel yeast cell surface display
system in which peptides are presented within the surface regions of the
transferrin molecule allowing selection of transferrin derivatives with
affinity for broad range of drug target sites in the context of the
final therapeutic product.