title: The low-temperature dynamic crossover phenomenon in protein hydration water: simulations vs experiments.
abstract: A super-Arrhenius-to-Arrhenius dynamic crossover phenomenon has been observed in the translational alpha-relaxation time and in the inverse of the self-diffusion constant both experimentally and by simulations for lysozyme hydration water in the temperature range of TL = 223 +/- 2 K. MD simulations are based on a realistic hydrated powder model, which uses the TIP4P-Ew rigid molecular model for the hydration water. The convergence of neutron scattering, nuclear magnetic resonance and molecular dynamics simulations supports the interpretation that this crossover is a result of the gradual evolution of the structure of hydration water from a high-density liquid to a low-density liquid form upon crossing of the Widom line above the possible liquid-liquid critical point of water.
authors.affiliation: Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Marco
authors.initials: M
authors.lastname: Lagi
authors.forename: Xiangqiang
authors.initials: X
authors.lastname: Chu
authors.forename: Chansoo
authors.initials: C
authors.lastname: Kim
authors.forename: Francesco
authors.initials: F
authors.lastname: Mallamace
authors.forename: Piero
authors.initials: P
authors.lastname: Baglioni
authors.forename: Sow-Hsin
authors.initials: SH
authors.lastname: Chen
mesh_terms: D003080:Cold Temperature; D003198:Computer Simulation; D004798:Enzymes / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009113:Muramidase / Q000737:chemistry; D009502:Neutrons; D011208:Powders; D011506:Proteins / Q000737:chemistry*; D012542:Scattering, Radiation; D014867:Water / Q000737:chemistry*
chemical_list: D004798:Enzymes; D011208:Powders; D011506:Proteins; D014867:Water; D006859:Hydrogen; D009113:Muramidase