Display of heterologous gene products on the Escherichia coli cell surfaceas fusion proteins with flagellin

We have developed a system for expressing and displaying recombinant protei ns, on the surface of Escherichia coli cells using the flagellin gene (hag) . In order to produce fusion proteins, DNA fragments encoding a small pepti de with 15 amino acid residues (P15), the constant region of the antibody L chain (region C), a single chain Fv (sFv) of an anti-porphyrin antibody, g reen fluorescent protein (GFP) and a bacterial alkaline phosphatase (BAP), respectively were inserted into the dispensable D3 domain encoded by hag. E ach fusion gene was expressed in LS, coli YK4516, a strain that lacks hag. The peptide linker P15 and the region C were efficiently expressed and disp layed in the flagellar fraction as fusion proteins. Although with lower eff iciency, sFv, BAP and GFP could also be expressed in the flagellar fraction . Therefore, this system is useful for epitope analysis and with some impro vements, the method could be useful for the expression of heterologous prot eins on the cell surface.