Dynamics of lysozyme and its hydration water under electric field

Journal Article · Wed Jan 01 04:00:00 EST 2014 · Journal of Biological Physics

DOI:https://doi.org/10.1007/s10867-014-9343-2· OSTI ID:1149393

Favi, Pelagie M ^[1]; Zhang, Qiu ^[1]; O'Neill, Hugh Michael ^[1]; Mamontov, Eugene ^[1]; Omar Diallo, Souleymane ^[1]; Palmer, Jeremy ^[2]

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1. ORNL
2. North Carolina State University

The effects of static electric field on the dynamics of lysozyme and its hydration water have been investigated by means of incoherent quasi-elastic neutron scattering (QENS). Measurements were performed on lysozyme samples, hydrated respectively with heavy water (D2O) to capture the protein dynamics, and with light water (H2O), to probe the dynamics of the hydration shell, in the temperature range from 210 < T < 260 K. The hydration fraction in both cases was about 0.38 gram of water per gram of dry protein. The field strengths investigated were respectively 0 kV/mm and 2 kV/mm ( 2 106 V/m) for the protein hydrated with D2O and 0 kV and 1 kV/mm for the H2O-hydrated counterpart. While the overall internal protons dynamics of the protein appears to be unaffected by the application of electric field up to 2 kV/mm, likely due to the stronger intra-molecular interactions, there is also no appreciable quantitative enhancement of the diffusive dynamics of the hydration water, as would be anticipated based on our recent observations in water confined in silica pores under field values of 2.5 kV/mm. This may be due to the difference in surface interactions between water and the two adsorption hosts (silica and protein), or to the existence of a critical threshold field value Ec 2 3 kV/mm for increased molecular diffusion, for which electrical breakdown is a limitation for our sample.

• Research Organization: Oak Ridge National Laboratory (ORNL); Spallation Neutron Source; Center for Structural Molecular Biology (CSMB)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1149393
• Journal Information: Journal of Biological Physics, Journal Name: Journal of Biological Physics Journal Issue: 2 Vol. 40; ISSN 0092-0606
• Country of Publication: United States
• Language: English

Related Subjects

DIffusion
Electric Field
Protein Dynamics
Quasi-Elastic Neutron Scatteirng