Comment on "Glass Transition in Biomolecules and the Liquid-Liquid Critical Point of Water"

S. R. ACCORDINO; D. C. MALASPINA,; J. A. RODRÍGUEZ FRIS; G. A. APPIGNANESI

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Año: 2011 vol. 106 p. 29801 - 29801

0031-9007

A recent Letter [1] investigated the relationship between dynamic transitions of biomolecules (lysozyme and DNA) and dynamic and thermodynamic properties of hydration water. This seminal work demonstrated that the so-called protein glass transition is (in two ways) ill-defined: It is not properly a glass transition nor due to the protein behavior. Rather, this phenomenon is shown to occur at the dynamic crossover in the diffusivity of the hydration water as a result of crossing the hypothesized liquid-liquid critical point (Widom line). One piece of evidence provided was the demonstration that the rate of change with temperature of the local order of hydration water molecules for both lysozyme and DNA presents a maximum at such crossover temperature [1]. However, there exist two problems on their way to this result which could lead to misleading results.