Chaperonins and Protein Folding: Unity and Disunity of Mechanisms [and Discussion]

• Published in: Philosophical transactions of the Royal Society of London. Series B. Biological sciences 1993-03, Vol.339 (1289), p.297-304
• Main Authors: Lorimer, George H., Todd, Matthew J., Viitanen, Paul V., Price, N. C., Jaenicke, R., F.-U. Hartl, Freedman, R. B., Yoshida, M., Welch, W. J., O'Hara, B.
• Format: Article
• Language: English
• Subjects: Aggregation; Animals; Bacterial Proteins - metabolism; Biochemistry; Chaperonin 10; Chaperonin 60; Chaperonins; Escherichia coli; Escherichia coli - genetics; Escherichia coli - metabolism; Heat-Shock Proteins - metabolism; Hydrolysis; Models, Biological; Molecules; Monomers; Protein Folding; Protein refolding; Proteins - metabolism; Ribulose-Bisphosphate Carboxylase - biosynthesis; Stoichiometry
• ISSN: 0962-8436; 1471-2970
• DOI: 10.1098/rstb.1993.0028

Chaperonin-facilitated folding of proteins involves two partial reactions. The first partial reaction, the formation of stable binary complexes between chaperonin-60 and non-native states of the target protein, is common to the chaperonin-facilitated folding of all target proteins investigated to date. The structural basis for this interaction is not presently understood. The second partial reaction, the dissociation of the target protein in a form committed to the native state, appears to proceed by a variety of mechanisms, dependent upon the nature of the target protein in question. Those target proteins (e.g. rubisco, rhodanese, citrate synthase) which require the presence of chaperonin-10, also appear to require the hydrolysis of ATP to bring about the dissociation of the target protein from chaperonin-60. With one exception (pre-$\beta $-lactamase) those target proteins which do not require the presence of chaperonin-10 to be released from chaperonin-60, also do not require the hydrolysis of ATP, since non-hydrolysable analogues of ATP support the release of the target protein in a state committed to the native state. The question of whether or not chaperonin-facilitated folding constitutes a catalysed event is addressed.