Nanobodies as solubilization chaperones for the expression and purification of inclusion-body prone proteins

Here, we report a new protocol for enhancing the soluble expression of inclusion body (IB)-prone proteins in E. coli using nanobodies (Nbs) as a molecular-specific chaperone. The specific intracellular binding between the cognate-Nbs and the antigen is successfully achieved and enables the formation of a soluble Nb-antigen complex in E. coli. We further expand this method by adding an epitope tag (EPEA-tag) to the target proteins, and the anti-EPEA Nb was intended to act as the chaperone for in vivo binding with the EPEA tag. Such substitution may develop a "multi-specific" Nb-chaperone that can simultaneously and effectively cope with different IB proteins of interest.