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The Energetics of a Three‐State Protein Folding System Probed by High‐Pressure Relaxation Dispersion NMR Spectroscopy
Author(s) -
Tugarinov Vitali,
Libich David S.,
Meyer Virginia,
Roche Julien,
Clore G. Marius
Publication year - 2015
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201505416
Subject(s) - compressibility , metastability , folding (dsp implementation) , chemistry , crystallography , relaxation (psychology) , thermodynamics , dispersion (optics) , bar (unit) , protein folding , physics , psychology , social psychology , biochemistry , organic chemistry , optics , meteorology , electrical engineering , engineering
The energetic and volumetric properties of a three‐state protein folding system, comprising a metastable triple mutant of the Fyn SH3 domain, have been investigated using pressure‐dependent 15 N‐relaxation dispersion NMR from 1 to 2500 bar. Changes in partial molar volumes (Δ V ) and isothermal compressibilities (Δ κ T ) between all the states along the folding pathway have been determined to reasonable accuracy. The partial volume and isothermal compressibility of the folded state are 100 mL mol −1 and 40 μL mol −1 bar −1 , respectively, higher than those of the unfolded ensemble. Of particular interest are the findings related to the energetic and volumetric properties of the on‐pathway folding intermediate. While the latter is energetically close to the unfolded state, its volumetric properties are similar to those of the folded protein. The compressibility of the intermediate is larger than that of the folded state reflecting the less rigid nature of the former relative to the latter.