Molecular Chaperone-like Properties of an Unfolded Protein, αs-Casein

摘要: All molecular chaperones known to date are well organized, folded protein molecules whose three-dimensional structure believed play a key role in the mechanism of substrate recognition and subsequent assistance folding. A common feature all nonprotein is propensity form aggregates very similar micellar aggregates. In this paper we show that αs-casein, abundant mammalian milk, which has no defined secondary tertiary but exits nature as aggregate, can prevent variety unrelated proteins/enzymes against thermal-, chemical-, or light-induced aggregation. It also prevents aggregation its natural substrates, whey proteins. αs-Casein interacts with partially unfolded proteins through solvent-exposed hydrophobic surfaces. The absence disulfide bridge free thiol groups sequence plays important preventing thermal caused by thiol-disulfide interchange reactions. Our results indicate αs-casein not only formation huge insoluble it inhibit accumulation soluble appreciable size. Unlike other chaperones, solubilize hydrophobically aggregated This seems have some characteristics cold shock protein, chaperone-like activity increases decrease temperature.