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Trifluoroethanol‐induced conformational transitions of proteins: Insights gained from the differences between α‐lactalbumin and ribonuclease A
Author(s) -
Gast Klaus,
Zirwer Dietrich,
MüllerFrohne Marlies,
Damaschun Gregor
Publication year - 1999
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 - 10.1110/ps.8.3.625
Subject(s) - molten globule , circular dichroism , ribonuclease , lactalbumin , chemistry , alpha lactalbumin , bovine pancreatic ribonuclease , folding (dsp implementation) , dynamic light scattering , protein folding , protein secondary structure , crystallography , biophysics , biochemistry , materials science , nanotechnology , biology , rna , nanoparticle , electrical engineering , gene , engineering
The trifluoroethanol (TFE)‐induced structural changes of two proteins widely used in folding experiments, bovine α‐lactalbumin, and bovine pancreatic ribonuclease A, have been investigated. The experiments were performed using circular dichroism spectroscopy in the far‐and near‐UV region to monitor changes in the secondary and tertiary structures, respectively, and dynamic light scattering to measure the hydrodynamic dimensions and the intermolecular interactions of the proteins in different conformational states. Both proteins behave rather differently under the influence of TFE: α‐lactalbumin exhibits a molten globule state at low TFE concentrations before it reaches the so‐called TFE state, whereas ribonuclease A is directly transformed into the TFE state at TFE concentrations above 40% (v/v). The properties of the TFE‐induced states are compared with those of equilibrium and kinetic intermediate states known from previous work to rationalize the use of TFE in yielding information about the folding of proteins. Additionally, we report on the properties of TFE/water and TFE/buffer mixtures derived from dynamic light scattering investigations under conditions used in our experiments.