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Strange kinetic phase in the extremely early folding process of β‐lactoglobulin
Author(s) -
Kamatari Yuji O.,
Nakamura Hironori K.,
Kuwata Kazuo
Publication year - 2007
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2007.08.023
Subject(s) - temperature jump , microsecond , kinetic energy , folding (dsp implementation) , phase (matter) , chemical physics , chemistry , protein folding , jump , fluorescence , kinetics , crystallography , thermodynamics , biophysics , physics , optics , biology , biochemistry , classical mechanics , electrical engineering , organic chemistry , quantum mechanics , engineering
A continuous‐wave probed laser‐induced temperature jump system was constructed and applied to monitor the changes in tryptophan fluorescence of the β‐lactoglobulin during its folding; the kinetic phases were traced from 300 ns to 10 ms after a temperature jump. Notably, an early phase with typical squeezed‐exponential characteristics, [exp{−( kt ) β }, β > 1.0], was observed around several tens of microseconds after the temperature jump, which is actually the earliest phase ever observed for β‐lactoglobulin. This process can be explained by conformational shift occurring within the unfolded ensemble (U → U′), which is followed by the non‐native intermediate (I) formation of this protein.