We report the ultrafast collective hydrogen-bond dynamics of water in the extended hydration layer of urea by using terahertz time-domain spectroscopy in the frequency region of 0.3-2.0 THz. The complex dielectric function has been fitted using a Debye relaxation model, and the timescales obtained are in the order of approximately 9 ps and 200 fs for bulk water; this exhibits a considerable acceleration beyond the 4 M urea concentration and indicates a possible disruption in the collective hydrogen-bonded water-network structure, which, in turn, provides an indirect support for the water "structure-breaking" ability of urea. With 5 M urea in the presence of different concentrations of trimethylamine-N-oxide (TMAO), it was found that these parameters essentially follow the trend observed for TMAO itself, which signifies that any possible disruption of the water structure by urea is outdone by the strong hydrogen-bonding ability of TMAO, which explains its ability to revive urea-denatured proteins to their respective native states.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/asia.201402696 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Interfacial vs confinement effects in the anisotropic frequency-dependent dielectric, THz and IR response of nanoconfined water.
J Chem Phys
December 2024
Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany.
We investigate the anisotropic frequency-dependent dielectric, THz and IR response of liquid water confined between two planar graphene sheets with force-field- and density-functional-theory-based molecular dynamics simulations. Using spatially resolved anisotropic spectra, we demonstrate the critical role of the volume over which the spectral response is integrated when reporting spatially averaged electric susceptibilities. To analyze the spectra, we introduce a unique decomposition into bulk, interfacial, and confinement contributions, which reveals that confinement effects on the spectra occur only for systems with graphene separation below 1.
View Article and Find Full Text PDFHidden water's influence on rhodopsin activation.
Biophys J
December 2024
Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona; Department of Physics, University of Arizona, Tucson, Arizona. Electronic address:
Structural biology relies on several powerful techniques, but these tend to be limited in their ability to characterize protein fluctuations and mobility. Overreliance on structural approaches can lead to omission of critical information regarding biological function. Currently there is a need for complementary biophysical methods to visualize these mobile aspects of protein function.
View Article and Find Full Text PDFModeling Infrared Spectroscopy of Nucleic Acids: Integrating Vibrational Non-Condon Effects with Machine Learning Schemes.
J Chem Theory Comput
November 2024
Department of Chemistry and Chemical Biology, Institute for Quantitative Biomedicine, Rutgers University, Piscataway, New Jersey 08854, United States.
Vibrational non-Condon effects, which describe how molecular vibrational transitions are influenced by a system's rotational and translational degrees of freedom, are often overlooked in spectroscopy studies of biological macromolecules. In this work, we explore these effects in the modeling of infrared (IR) spectra for nucleic acids in the 1600-1800 cm region. Through electronic structure calculations, we reveal that the transition dipole moments of the C═O and C═C stretching modes in nucleobases are highly sensitive to solvation, hydrogen bonding, and base stacking conditions.
View Article and Find Full Text PDFDynamic permittivity of confined water under a static background field.
J Chem Phys
October 2024
Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23221, USA.
Molecular and collective reorientations in interfacial water are by-and-large decelerated near surfaces subjected to outgoing electric fields (pointing from surface to liquid, i.e., when the surface carries positive charge).
View Article and Find Full Text PDFFast Collective Hydrogen-Bond Dynamics in Hexafluoroisopropanol Related to its Chemical Activity.
Angew Chem Int Ed Engl
December 2024
Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, The Netherlands.
Using fluorinated mono-alcohols, in particular hexafluoro-isopropanol (HFIP), as a solvent can enhance chemical reaction rates in a spectacular manner. Previous work has shown evidence that this enhancement is related to the hydrogen-bond structure of these liquids. Here, we investigate the hydrogen-bond dynamics of HFIP and compare it to that of its non-fluorinated analog, isopropanol.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!