Denaturant m values and heat capacity changes: Relation to changes in accessible surface areas of protein unfolding
Article first published online: 31 DEC 2008
Copyright © 1995 The Protein Society
Volume 4, Issue 10, pages 2138–2148, October 1995
How to Cite
Myers, J. K., Nick Pace, C. and Martin Scholtz, J. (1995), Denaturant m values and heat capacity changes: Relation to changes in accessible surface areas of protein unfolding. Protein Science, 4: 2138–2148. doi: 10.1002/pro.5560041020
- Issue published online: 31 DEC 2008
- Article first published online: 31 DEC 2008
- Manuscript Accepted: 13 JUL 1995
- Manuscript Received: 15 MAY 1995
- The National Institutes of Health. Grant Number: R01 GM37039 to C.N.P. and R29 GM52483 to J.M.S.
- The Robert A. Welch foundation. Grant Number: A-1060 to C.N.P. and A-1281 to J.M.S.
- NIH. Grant Number: T32 GM08523
- guanidine hydrochloride;
- heat capacity changes;
- m values;
- protein folding;
- protein stability;
- solvent-accessible surface area;
Denaturant m values, the dependence of the free energy of unfolding on denaturant concentration, have been collected for a large set of proteins. The m value correlates very strongly with the amount of protein surface exposed to solvent upon unfolding, with linear correlation coefficients of R = 0.84 for urea and R = 0.87 for guanidine hydrochloride. These correlations improve to R = 0.90 when the effect of disulfide bonds on the accessible area of the unfolded protein is included. A similar dependence on accessible surface area has been found previously for the heat capacity change (ΔCp), which is confirmed here for our set of proteins. Denaturant m values and heat capacity changes also correlate well with each other. For proteins that undergo a simple two-state unfolding mechanism, the amount of surface exposed to solvent upon unfolding is a main structural determinant for both m values and ΔCp.