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dc.contributor.authorCharkhesht, Ali
dc.contributor.authorRegmi, Chola K.
dc.contributor.authorMitchell-Koch, Katie R.
dc.contributor.authorCheng, Shengfeng
dc.contributor.authorVinh, Nguyen Q.
dc.identifier.citationAli Charkhesht, Chola K. Regmi, Katie R. Mitchell-Koch, Shengfeng Cheng, and Nguyen Q. Vinh. High-precision megahertz-to-terahertz dielectric spectroscopy of protein collective motions and hydration dynamics. Journal of Physical Chemistry B, 2018 122 (24), 6341-6350en_US
dc.descriptionClick on the DOI link to access the article (may not be free).en_US
dc.description.abstractThe low-frequency collective vibrational modes in proteins as well as the protein-water interface have been suggested as dominant factors controlling the efficiency of biochemical reactions and biological energy transport. It is thus crucial to uncover the mystery of the hydration structure and dynamics as well as their coupling to collective motions of proteins in aqueous solutions. Here, we report dielectric properties of aqueous bovine serum albumin protein solutions as a model system using an extremely sensitive dielectric spectrometer with frequencies spanning from megahertz to terahertz. The dielectric relaxation spectra reveal several polarization mechanisms at the molecular level with different time constants and dielectric strengths, reflecting the complexity of protein-water interactions. Combining the effective-medium approximation and molecular dynamics simulations, we have determined collective vibrational modes at terahertz frequencies and the number of water molecules in the tightly bound and loosely bound hydration layers. High-precision measurements of the number of hydration water molecules indicate that the dynamical influence of proteins extends beyond the first solvation layer, to around 7 angstrom distance from the protein surface, with the largest slowdown arising from water molecules directly hydrogen-bonded to the protein. Our results reveal critical information of protein dynamics and protein-water interfaces, which determine biochemical functions and reactivity of proteins.en_US
dc.description.sponsorshipThomas F. and Kate Miller Jeffress Memorial Trust, Bank of America, N.A., Trustee via the Jeffress Trust Awards Program in Interdisciplinary Research. Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund (PRF # 56103-DNI6 and 55975-DNI6) for partial support of this research. This work was also supported by a grant from the Institute of Critical Technology and Applied Sciences (ICTAS) at Virginia Tech.en_US
dc.publisherAmerican Chemical Societyen_US
dc.relation.ispartofseriesJournal of Physical Chemistry B;v.122:no.24
dc.subjectPump-probe spectroscopyen_US
dc.subjectLiquid wateren_US
dc.titleHigh-precision megahertz-to-terahertz dielectric spectroscopy of protein collective motions and hydration dynamicsen_US
dc.rights.holder© 2018, American Chemical Societyen_US

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