Pawlus S, Khodadadi S, Sokolov A P
Department of Polymer Science, The University of Akron, Akron, Ohio 44321, USA.
Phys Rev Lett. 2008 Mar 14;100(10):108103. doi: 10.1103/PhysRevLett.100.108103.
Dielectric spectroscopy studies of hydrated protein demonstrate smooth temperature variations of conductivity. This observation suggests no cusplike fragile-to-strong crossover (FSC) in the protein's hydration water. The FSC at T approximately 220 K was postulated recently on the basis of neutron scattering studies [Chen, Proc. Natl. Acad. Sci. U.S.A. 103, 9012 (2006)] and was proposed to be the main cause for the dynamic transition in hydrated proteins. Following Swenson et al. , we ascribe the neutron results to a secondary relaxation. We emphasize that no cusplike solvent behavior is required for the protein's dynamic transition.
水合蛋白质的介电谱研究表明，电导率随温度呈平滑变化。这一观察结果表明，蛋白质的水合水不存在类似尖点的从脆弱到强壮的转变（FSC）。最近，基于中子散射研究[Chen，Proc. Natl. Acad. Sci. U.S.A. 103, 9012 (2006)]推测在T约220 K时存在FSC，并提出这是水合蛋白质动态转变的主要原因。按照斯文森等人的观点，我们将中子研究结果归因于二级弛豫。我们强调，蛋白质的动态转变不需要类似尖点的溶剂行为。
