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Denaturant m values and heat capacity changes: Relation to changes in accessible surface areas of protein unfolding
Author(s) -
Myers Jeffrey K.,
Nick Pace C.,
Martin Scholtz J.
Publication year - 1995
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560041020
Subject(s) - guanidine , accessible surface area , heat capacity , chemistry , surface protein , thermodynamics , crystallography , solvent , urea , protein folding , computational chemistry , biochemistry , biology , physics , virology
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 (ΔC p ), 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 Δ C p .