Non-Chromatographic Strategies for Protein Refolding
Saurabh Gautam, Priyanka Dubey, Gulam Mohmad Rather and Munishwar N. Gupta
Affiliation: Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
Overexpression of recombinant proteins in bacterial systems (such as E. coli) often leads to formation of inactive
and insoluble ‘inclusion bodies’. Protein refolding refers to folding back the proteins after solubilizing/unfolding the
misfolded proteins of the inclusion bodies. Protein aggregation, a concentration dependent phenomenon, competes with
refolding pathway. The refolding strategies largely aim at reducing aggregation and/or promoting correct folding. This review
focuses on non-chromatographic strategies for refolding like dilution, precipitation, three phase partitioning and
macro-(affinity ligand) facilitated three phase partitioning. The nanomaterials which disperse well in aqueous buffers are
also discussed in the context of facilitating protein refolding. Apart from general results with these methods, the review also covers the use of non-chromatographic methods in protein refolding in the patented literature beyond 2000. The patented literature generally describes use of cocktail of additives which results in increase in refolding yield. Such additives include low concentration of chaotropic agents, redox systems, ions like SO4 2- and Cl-, amines, carboxylic acids and surfactants.
Some novel approaches like use of a “pressure window” or ionic liquids for refolding and immobilized diselenide
compounds for ensuring correct –S–S– bonds pairing have also been discussed in various patents. In most of the
patented literature, focus naturally has been on refolding in case of pharmaceutical proteins.
Keywords: Additives, affinity precipitation, inclusion bodies, macro-(affinity ligand) facilitated three phase partitioning, protein refolding, pseudochaperonins, smart polymers, three phase partitioning.
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