TY  - JOUR
AU  - Kämpf, Kerstin
AU  - Demuth, Dominik
AU  - Zamponi, Michaela
AU  - Wuttke, Joachim
AU  - Vogel, Michael
TI  - Quasielastic neutron scattering studies on couplings of protein and water dynamics in hydrated elastin
JO  - The journal of chemical physics
VL  - 152
IS  - 24
SN  - 1089-7690
CY  - Melville, NY
PB  - American Institute of Physics
M1  - FZJ-2020-02445
SP  - 245101 -
PY  - 2020
AB  - erforming quasielastic neutron scattering measurements and analyzing both elastic and quasielasic contributions, we study protein and water dynamics of hydrated elastin. At low temperatures, hydration-independent methyl group rotation dominates the findings. It is characterized by a Gaussian distribution of activation energies centered at about Em = 0.17 eV. At ∼195 K, coupled protein–water motion sets in. The hydration water shows diffusive motion, which is described by a Gaussian distribution of activation energies with Em = 0.57 eV. This Arrhenius behavior of water diffusion is consistent with previous results for water reorientation, but at variance with a fragile-to-strong crossover at ∼225 K. The hydration-related elastin backbone motion is localized and can be attributed to the cage rattling motion. We speculate that its onset at ∼195 K is related to a secondary glass transition, which occurs when a β relaxation of the protein has a correlation time of τβ ∼ 100 s. Moreover, we show that its temperature-dependent amplitude has a crossover at the regular glass transition Tg = 320 K of hydrated elastin, where the α relaxation of the protein obeys τα ∼ 100 s. By contrast, we do not observe a protein dynamical transition when water dynamics enters the experimental time window at ∼240 K.
LB  - PUB:(DE-HGF)16
C6  - pmid:32610976
UR  - <Go to ISI:>//WOS:000546996600001
DO  - DOI:10.1063/5.0011107
UR  - https://juser.fz-juelich.de/record/877757
ER  -