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A Simple Mechanism Underlying the Effect of Protecting Osmolytes on Protein Folding.

Authors :
Saladino G
Marenchino M
Pieraccini S
Campos-Olivas R
Sironi M
Gervasio FL
Source :
Journal of chemical theory and computation [J Chem Theory Comput] 2011 Nov 08; Vol. 7 (11), pp. 3846-52. Date of Electronic Publication: 2011 Oct 06.
Publication Year :
2011

Abstract

Osmolytes are small organic compounds that confer to the cell an enhanced adaptability to external conditions. Many osmolytes not only protect the cell from osmotic stress but also stabilize the native structure of proteins. While simplified models able to predict changes to protein stability are available, a general physicochemical explanation of the underlying microscopic mechanism is still missing. Here, we address this issue by performing very long all-atom MD simulations, free energy calculations, and experiments on a well-characterized mini-protein, the villin headpiece. Comparisons between the folding free energy landscapes in pure water and osmolyte solutions, together with experimental validation by means of circular dichroism, unfolding experiments, and NMR, led us to formulate a simple hypothesis for the protecting mechanism. Taken together, our results support a novel mechanistic explanation according to which the main driving force behind native state protection is a change in the solvent rotational diffusion.

Details

Language :
English
ISSN :
1549-9618
Volume :
7
Issue :
11
Database :
MEDLINE
Journal :
Journal of chemical theory and computation
Publication Type :
Academic Journal
Accession number :
26598273
Full Text :
https://doi.org/10.1021/ct200471w