Full-Length CotX Is Required for Display of Heterologous Proteins on Bacillus subtilis Spores

Bacillus subtilis spore display is a versatile technology enabling presentation of heterologous proteins on the surface of recombinant spores. Undoubted benefits of such system include easiness of construction, facility of spore production and handling, enhanced stability of displayed proteins. In spite of these, the efficient spore display faces some challenges which need to be taken on in the process of design and construction. In this study, we attempted to determine a minimal anchoring motif of the crust protein CotX which can be used for display of heterologous protein on the spore surface. We succeeded in presenting mChery fluorescent protein as N-terminal fusion of CotX. Nevertheless, our results suggest that only the full-length CotX could serve as anchor in spore display, since fusions with truncated variants of this protein were not detected in the spore coat and were degraded in the cell.