Lifetimes of intermediates in the beta -sheet to alpha -helix transition of beta -lactoglobulin by using a diffusional IR mixer.
The extremely slow alpha-helix/beta-sheet transition of proteins is a crucial step in amylogenic diseases and represents an internal rearrangement of local contacts in an already folded protein. These internal structural rearrangements within an already folded protein are a critical aspect of biological action and are a product of conformational flow along unknown metastable local minima of the energy landscape of the compact protein. We use a diffusional IR mixer with time-resolved Fourier transform IR spectroscopy capable of 400-micros time resolution to show that the trifluoroethanol driven beta-sheet to alpha-helix transition of beta-lactoglobulin proceeds via a compact beta-sheet intermediate with a lifetime of 7 ms, small compared with the overall folding time of beta-lactoglobulin.
Kauffmann
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E
Lehrstuhl für Biophysik, Ruhr-Universität Bochum, 44780 Bochum, Germany.
Darnton
N C
NC
Austin
R H
RH
Batt
C
C
Gerwert
K
K
D004058:Diffusion; D007782:Lactoglobulins / Q000737:chemistry*; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared
D007782:Lactoglobulins