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Updated: Jul 19, 2026

NMR 15N Relaxation Experiments for the Investigation of Picosecond to Nanoseconds Structural Dynamics of Proteins
Published on: November 1, 2024
Kinetics of helix-coil transition of polypeptides in solution by the relaxation methods
1Department of Chemistry, Faculty of Science, Hiroshima University, Hiroshima 730, Japan.
Abstract:
Relaxation phenomena were studied in aqueous solutions of poly (alpha-L-glutamic acid) (Glu)n and poly (alpha-L-lysine) (Lys)n under various conditions using the electric field pulse method with detection by conductivity change. The relaxation time for the (Glu)n has a maximum value at the midpoint of the helix-coil transition. Some possible mechanisms are discussed and the observed relaxation phenomenon is attributed to the helix-coil transition. In the case of (Lys)n, the relaxation time as a function of pH exhibits two maxima. One is assigned to a proton transfer reaction and the other to the helix-coil transition. Using the Schwarz's theory the rate constants of the helix growth step for both (Glu)n and (Lys)n are estimated. The difference in the activation parameters for (Glu)n and (Lys)n is discussed.
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