Journal article
Osmolyte-induced changes in protein conformational equilibria
Biopolymers, v 53(4)
05 Apr 2000
PMID: 10685050
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Abstract
Examining solute-induced changes in protein conformational equilibria is a long-standing method for probing the role of water in maintaining protein stability. Interpreting the molecular details governing the solute-induced effects, however, remains controversial. We present experimental and theoretical data for osmolyte-induced changes in the stabilities of the A and N states of yeast iso-1-ferricytochrome c. Using polyol osmolytes of increasing size, we observe that osmolytes alone induce A-state formation from acid-denatured cytochrome c and N state formation from the thermally denatured protein. The stabilities of the A and N states increase linearly with osmolyte concentration. Interestingly, osmolytes stabilize the A state to a greater degree than the N state. To interpret the data, we divide the free energy for the reaction into contributions from nonspecific steric repulsions (excluded volume effects) and from binding interactions. We use scaled particle theory (SPT) to estimate the free energy contributions from steric repulsions, and we estimate the contributions from water–protein and osmolyte–protein binding interactions by comparing the SPT calculations to experimental data. We conclude that excluded volume effects are the primary stabilizing force, with changes in water–protein and solute–protein binding interactions making favorable contributions to stability of the A state and unfavorable contributions to the stability of the N state. The validity of our interpretation is strengthened by analysis of data on osmolyte-induced protein stabilization from the literature, and by comparison with other analyses of solute-induced changes in conformational equilibria.
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Details
- Title
- Osmolyte-induced changes in protein conformational equilibria
- Creators
- Aleister J. Saunders - University of North Carolina at Chapel HillPaula R. Davis-Searles - University of North Carolina at Chapel HillDevon L. Allen - University of North Carolina at Chapel HillGary J. Pielak - University of North Carolina at Chapel HillDorothy A. Erie - University of North Carolina at Chapel Hill
- Publication Details
- Biopolymers, v 53(4)
- Publisher
- John Wiley & Sons, Inc
- Number of pages
- 15
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Biology
- Web of Science ID
- WOS:000086467400002
- Scopus ID
- 2-s2.0-1842473533
- Other Identifier
- 991021448027204721
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InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Web of Science research areas
- Biochemistry & Molecular Biology
- Biophysics