Heat Shock Protein-like Activity of a Nanogel Artificial Chaperone for Citrate Synthase

Molecular chaperone–like activity for the refolding of citrate synthase (CS) was investigated using nanometer-sized (<100nm) polymer hydrogels (nanogels) composed of cholesterol-bearing pullulan (CHP). We reported that CHP nanogels selectively interact with proteins (guests) as the host. CHP nanogels effectively prevented protein aggregation upon heating by complexation with denatured proteins. The enzyme activity of CS recovered in high yields after the addition of cyclodextrins. CHP nanogels assisted protein refolding in a manner similar to the mechanism with molecular chaperones such as GroEL. The present nanogel system could be a useful tool for the refolding and stabilization of unstable proteins.