Dynamical transition, hydrophobic interface, and the temperature dependence of electrostatic fluctuations in proteins

Abstract

Molecular dynamics simulations have revealed a dramatic increase, with increasing temperature, of the amplitude of electrostatic fluctuations caused by water at the active site of metalloprotein plastocyanin. The increased breadth of electrostatic fluctuations, expressed in terms of the reorganization energy of changing the redox state of the protein, is related to the formation of the hydrophobic protein/water interface allowing large-amplitude collective fluctuations of the water density in the protein's first solvation shell. On the top of the monotonic increase of the reorganization energy with increasing temperature, we have observed a spike at 220 K also accompanied by a significant slowing of the exponential collective Stokes shift dynamics. In contrast to the local density fluctuations of the hydration-shell waters, these spikes might be related to the global property of the water solvent crossing the Widom line.

9 pages, 8 figures

References in corpus (6)

• Relation Between the Widom line and the Strong-Fragile Dynamic Crossover in Systems with a Liquid-Liquid Phase Transition
• Observation of Fragile-to-Strong Dynamic Crossover in Protein Hydration Water
• Glass transition in biomolecules and the liquid-liquid critical point of water
• Liquid-liquid phase transitions in supercooled water studied by computer simulations of various water models
• Experimental Evidence of Fragile-to-Strong Dynamic Crossover in DNA Hydration Water
• Redox Entropy of Plastocyanin: Developing a Microscopic View of Mesoscopic Polar Solvation

Cited by in corpus (3)

• On the alternatives for bath correlators and spectral densities from mixed quantum-classical simulations
• Terahertz response of dipolar impurities in polar liquids: On anomalous dielectric absorption of protein solutions
• Depth dependent dynamics in the hydration shell of a protein