J. Phys. I France
Volume 7, Numéro 3, March 1997
Page(s) 553 - 560
DOI: 10.1051/jp1:1997174
J. Phys. I France 7 (1997) 553-560

A Kinetic Model for Chaperonin Assisted Folding of Proteins

Henri Orland1 and D. Thirumalai2

1  CEA, Service de Physique Théorique, CE-Saclay, 91191 Gif-sur-Yvette Cedex, France
2  Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742-2341, USA

(Received 17 July 1996, received in final form 22 November 1996, accepted 26 November 1996)

A master equation formalism is used to account for the possible kinetic action of chaperonin assisted folding of proteins. The model is based on the assumption that chaperonins rescue misfolded protein structures and stochastically provide them pathways to reach the native state by a mechanism involving ATP hydrolysis. We assume that the misfolded structures are characterized by distinct free energies and that these structures are connected to the native conformation by a suitable transition probabilities. The chaperonins do not recognize the native state. For this model it is shown that in the presence of chaperonins the native state is populated exponentially. The exponential population of the native state, which is in accord with experiments, is independent of the distribution of the free energies of the misfolded structures as well as the transition probabilities connecting them to the native state.

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