The folding process of a protein is inherently error-prone, owing to the large number of possible conformations that a protein chain can adopt. Partially folded or misfolded proteins typically expose hydrophobic surfaces and tend to form dysfunctional protein aggregates. Therefore, materials that can stabilize unfolded proteins and then efficiently assist them refolding to its bioactive form are of significant interest. Inspired by natural chaperonins, we have synthesized a series of polymeric nanochaperones that can facilitate the refolding of denatured proteins with a high recovery efficiency (up to 97%). Such nanochaperones possess phase-separated structure with hydrophobic microdomains on the surface. This structure allows nanochaperones to stabilize denatured proteins by binding them to the hydrophobic microdomains. We have also investigated the mechanism by which nanochaperones assist the protein refolding and established the design principles of nanochaperones in order to achieve effective recovery of a certain protein from their denatured forms. With a carefully designed composition of the microdomains according to the surface properties of the client proteins, the binding affinity between the hydrophobic microdomain and the denatured protein molecules can be tuned precisely, which enables the self-sorting of the polypeptides and the refolding of the proteins into their bioactive states. This work provides a feasible and effective strategy to recover inclusion bodies to their bioactive forms, which has potential to reduce the cost of the manufacture of recombinant proteins significantly.
Keywords: inclusion body; molecular chaperone; nanochaperone; protein refolding; self-assembly.