Surface-display of recombinant proteins on bacterial exosporium and its biotechnological applications

Abstract

We developed an innovative genetic immobilization method by expressing recombinant proteins on the surface of bacterial spore. An outer spore surface protein of Bacillus cereus group, exosporium, was used as fusion partner to display recombinant proteins. The stability of the exosporiumanchored proteins on extreme conditions, heat, solvent and etc, was investigated, very high because of resistance of spore matrix. Thus, the efficient surface expression on exosporium surrounds Bacillus spores as vehicle for efficient heterologous protein presentation, together with the high stability, makes the spore-presented proteins to powerful in vivo immobilized biomolecules. Flow cytometry, fluorescence assay and confocal laser scanning microscopy were used to monitor surface expression of recombinant proteins on purified spores. The surface-display systems of DNA, peptide/protein and antigen/antibody to the exosporium were studied for biotechnological applications, such as DNA hybridization assay, peptide/protein and antigen/antibody interaction assay. As in this reason, it has many potential capacities to biotechnological applications. And also, this exosporium protein could be used anchoring motif for cell surface display in Escherichia coli. Enhanced green fluorescent protein and streptavidin were successfully displayed by exosporium protein in E. coli.