On the origins of apparent fragile-to-strong transition of protein hydration waters

Abstract

2H NMR is used to study the mechanisms for the reorientation of protein hydration water. In the past, crossovers in temperature-dependent correlation times were reported at T_x1=225K (X1) and T_x2=200K (X2). We show that neither X1 nor X2 are related to a fragile-to-strong transition. Our results rule out an existence of X1. Also, they indicate that water performs thermally activated and distorted tetrahedral jumps at T<T_x2, implying that X2 originates in an onset of this motion, which may be related to a universal defect diffusion in materials with defined hydrogen-bond networks.

arXiv comment4 pages, 3 figures

References in corpus (4)

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• Glass transition in biomolecules and the liquid-liquid critical point of water
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Cited by in corpus (10)

• The Dynamic Transition of Protein Hydration Water
• NMR Studies on the Temperature-Dependent Dynamics of Confined Water
• NMR and dielectric studies of hydrated collagen and elastin: Evidence for a delocalized secondary relaxation
• Dynamically Slow Processes in Supercooled Water Confined Between Hydrophobic Plates
• Dynamics of Protein Hydration Water
• Analytic treatment of nuclear spin-lattice relaxation for diffusion in a cone model
• The Boson peak in supercooled water
• Nuclear spin-lattice relaxation from fractional wobbling in a cone
• 2H and 13C NMR studies on the temperature-dependent water and protein dynamics in hydrated elastin, myoglobin and collagen
• More than one dynamic crossover in protein hydration water