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Side‐chain conformational entropy in protein folding
Author(s) -
Doig Andrew J.,
Sternberg Michael J. E.
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.5560041101
Subject(s) - conformational isomerism , conformational entropy , side chain , entropy (arrow of time) , protein folding , chemistry , entropy of fusion , thermodynamics , configuration entropy , crystallography , physics , molecule , enthalpy of fusion , biochemistry , organic chemistry , differential scanning calorimetry , polymer
Abstract An important, but often neglected, contribution to the thermodynamics of protein folding is the loss of entropy that results from restricting the number of accessible side‐chain conformers in the native structure. Conformational entropy changes can be found by comparing the number of accessible rotamers in the unfolded and folded states, or by estimating fusion entropies. Comparison of several sets of results using different techniques shows that the mean conformational free energy change (TΔS) is 1 kcal‐mol −1 per side chain or 0.5 kcal‐mol −1 per bond. Changes in vibrational entropy appear to be negligible compared to the entropy change resulting from the loss of accessible rotamers. Side‐chain entropies can help rationalize α‐helix propensities, predict protein/inhibitor complex structures, and account for the distribution of side chains on the protein surface or interior.