Molecular chaperones: A revolutionary approach for increased solubility of recombinant mAbs from bacterial and yeast systems

Recombinant protein expression has revolutionized biotechnology, enabling the production of therapeutic proteins, enzymes, and antibodies with high specificity and functionality. Escherichia coli can be a prominent host for recombinant protein production due to its rapid growth, well-characterized genetics, and cost-effectiveness. However, the formation of insoluble protein aggregates, misfolding, and stability issues are significant challenges. This review explores the integration of molecular chaperones such as GroEL/GroES, DnaK/DnaJ/GrpE, and Skp in recombinant systems to enhance folding, solubility, and activity of recombinant monoclonal antibodies (mAbs). It also examines advances in co-expression strategies, secretion pathways, and the role of engineered host strains in overcoming these bottlenecks. Further, the review highlights comparative approaches in other expression systems in yeast, including Saccharomyces cerevisiae and Pichia pastoris, focusing on the molecular chaperone-assisted folding of full-length and fragmented mAbs using Hsp70-90 (analogs of DnaJ and K, respectively), tailless complex polypeptide 1 ring complex (TRiC), and ribosome-associated complex (RAC)/nascent polypeptide-associated complex (NAC) system. Innovations such as the application of polymer nanoparticles as artificial chaperones and mRNA engineering for co-translational folding underscore the potential for optimizing recombinant protein production. Collectively, these findings offer a thorough grasp of the role of chaperones and engineering strategies in improving mAbs quality, with implications for biopharmaceutical manufacturing and industrial applications.