The molecular chaperone GroEL in complex with denatured proteins: increasing stability against temperature and trypsin action

Abstract

One of the functions of the Escherichia coli heat shock protein GroEL (HSP60) is its interaction with polypeptide chains lacking a rigid tertiary structure and prevention of their irreversible aggregation both in vivo and in vitro. Here we investigated the effect of denatured substrate proteins (lysozyme, pepsin and serum albumin) on GroEL structural stability against temperature (differential scanning microcalorimetry) and protease action (limited trypsinolysis). It was shown that the interaction with denatured proteins increases GroEL stability, the greater the molecular weight of denatured substrate proteins, the higher the GroEL stability. The results are important for understanding the mechanism of the substrate protein interaction with the chaperone and the principle of GroEL structural organization. Refs 22. Figs 2. Tables 1.