Relationships between Molecular Structure of Carbohydrates and their Dynamic Hydration Shells Revealed by Terahertz Time-Domain Spectroscopy

Despite more than a century of research on the hydration of biomolecules, the hydration of carbohydrates is insufficiently studied. An approach to studying dynamic hydration shells of carbohydrates in aqueous solutions based on terahertz time-domain spectroscopy assay is developed in the current work. Monosaccharides (glucose, galactose, galacturonic acid) and polysaccharides (dextran, amylopectin, polygalacturonic acid) solutions were studied. The contribution of the dissolved carbohydrates was subtracted from the measured dielectric permittivities of aqueous solutions based on the corresponding effective medium models. The obtained dielectric permittivities of the water phase were used to calculate the parameters describing intermolecular relaxation and oscillatory processes in water. It is established that all of the analyzed carbohydrates lead to the increase of the binding degree of water. Hydration shells of monosaccharides are characterized by elevated numbers of hydrogen bonds and their mean energies compared to undisturbed water, as well as by elevated numbers and the lifetime of free water molecules. The axial orientation of the OH(4) group of sugar facilitates a wider distribution of hydrogen bond energies in hydration shells compared to equatorial orientation. The presence of the carboxylic group affects water structure significantly. The hydration of polysaccharides is less apparent than that of monosaccharides, and it depends on the type of glycosidic bonds.

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A Study of the Effect of a Protein on the Structure of Water in Solution Using Terahertz Time-Domain Spectroscopy

Applied Spectroscopy ◽

10.1177/0003702817735551 ◽

2017 ◽

Vol 72 (2) ◽

pp. 257-267 ◽

Cited By ~ 16

Author(s):

Nikita Penkov ◽

Valery Yashin ◽

Eugeny Fesenko ◽

Andrew Manokhin ◽

Eugeny Fesenko

Keyword(s):

Aqueous Solutions ◽

Aqueous Phase ◽

Time Domain ◽

Relaxation Times ◽

Free Water ◽

Model Parameters ◽

Biological Macromolecules ◽

Terahertz Time Domain Spectroscopy ◽

Time Domain Spectroscopy ◽

Hydration Shells

Terahertz time-domain spectroscopy (THz-TDS) was used to determine the spectra (range = 1.2–120 cm−1) of aqueous solutions of bovine serum albumin (BSA) at pH range 2.5–10. Under each of the selected pH, BSA molecules exist in a different conformation, compared to other pH values. The spectra were used to calculate the functions of the dielectric permittivity of BSA solutions. Dielectric functions of the aqueous phase of BSA solutions were calculated based on the Bruggeman model, without the contribution of BSA itself. Fitting of the dielectric functions was performed using a model which includes three water spectral bands: two relaxation bands with relaxation times of about 8.28 and 0.3 ps and a vibrational band with a maximum of about 180 cm−1. The parameters of these bands were determined through fitting and physical interpretation at the molecular level can be provided for each of them. A comparison between the values of model parameters of solutions with BSA and without BSA allowed to conclude that the main effect of BSA is the formation of strongly bound hydration shells in the immediate proximity to the protein molecule. At the same time, the structure of more distant layers of the hydration shells is destroyed, with an increased formation of free water molecules. Some differences are observed in the effect of different BSA conformations on the aqueous phase of solution. The proposed approach can be generalized and applied for studying of a wide class of biological macromolecules in aqueous solutions.

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Hydration Shells of DPPC Liposomes from the Point of View of Terahertz Time-Domain Spectroscopy

Applied Spectroscopy ◽

10.1177/0003702820949285 ◽

2020 ◽

pp. 000370282094928

Author(s):

Nikita V. Penkov ◽

Valery A. Yashin ◽

Konstantin N. Belosludtsev

Keyword(s):

Time Domain ◽

Liquid Crystalline ◽

Dynamic Properties ◽

Free Water ◽

Point Of View ◽

Terahertz Time Domain Spectroscopy ◽

Hydration Properties ◽

Water Binding ◽

Time Domain Spectroscopy ◽

Hydration Shells

Analysis of structural and dynamic properties of water in suspensions of liposomes composed from 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) in three phase states (gel, rippled gel, liquid crystalline phase) by means of terahertz time-domain spectroscopy in 0.3–3.3 THz range was conducted in the current work. Fraction of free water molecules in DPPC liposome suspension was shown to decrease with temperature (compared to the analogous aqueous solution without liposomes), and intermolecular water binding was enhanced. The most crucial changes occur during gel-rippled gel phase transition (pretransition): at temperatures below pretransition point, liposomes alleviate water binding degree, while at temperatures above the transition point, they enhance water binding. This study has demonstrated the high information content of the terahertz time-domain spectroscopy method for exploring the hydration properties of phospholipids in water.

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Hydration Shells of DNA from the Point of View of Terahertz Time-Domain Spectroscopy

International Journal of Molecular Sciences ◽

10.3390/ijms222011089 ◽

2021 ◽

Vol 22 (20) ◽

pp. 11089

Author(s):

Nadezda A. Penkova ◽

Mars G. Sharapov ◽

Nikita V. Penkov

Keyword(s):

Time Domain ◽

Hydration Shell ◽

Bound Water ◽

Free Water ◽

Point Of View ◽

Water Molecules ◽

Terahertz Time Domain Spectroscopy ◽

Time Domain Spectroscopy ◽

Effective Medium Model ◽

Hydration Shells

Hydration plays a fundamental role in DNA structure and functioning. However, the hydration shell has been studied only up to the scale of 10–20 water molecules per nucleotide. In the current work, hydration shells of DNA were studied in a solution by terahertz time-domain spectroscopy. The THz spectra of three DNA solutions (in water, 40mm MgCl2 and 150 mM KCl) were transformed using an effective medium model to obtain dielectric permittivities of the water phase of solutions. Then, the parameters of two relaxation bands related to bound and free water molecules, as well as to intermolecular oscillations, were calculated. The hydration shells of DNA differ from undisturbed water by the presence of strongly bound water molecules, a higher number of free molecules and an increased number of hydrogen bonds. The presence of 40 mM MgCl2 in the solution almost does not alter the hydration shell parameters. At the same time, 150 mM KCl significantly attenuates all the found effects of hydration. Different effects of salts on hydration cannot be explained by the difference in ionic strength of solutions, they should be attributed to the specific action of Mg2+ and K+ ions. The obtained results significantly expand the existing knowledge about DNA hydration and demonstrate a high potential for using the THz time-domain spectroscopy method.

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Determination of Alcohol Concentration in Aqueous Solutions and Food Analysis using Reflection Terahertz Time-Domain Spectroscopy

Optical Terahertz Science and Technology ◽

10.1364/otst.2007.mb2 ◽

2007 ◽

Cited By ~ 1

Author(s):

Uffe Møller ◽

Hannes Merbold ◽

Jacob Riis Folkenberg ◽

Peter Uhd Jepsen

Keyword(s):

Aqueous Solutions ◽

Food Analysis ◽

Time Domain ◽

Alcohol Concentration ◽

Terahertz Time Domain Spectroscopy ◽

Time Domain Spectroscopy

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Salt effects on the picosecond dynamics of lysozyme hydration water investigated by terahertz time-domain spectroscopy and an insight into the Hofmeister series for protein stability and solubility

Physical Chemistry Chemical Physics ◽

10.1039/c5cp06324h ◽

2016 ◽

Vol 18 (22) ◽

pp. 15060-15069 ◽

Cited By ~ 24

Author(s):

Katsuyoshi Aoki ◽

Kentaro Shiraki ◽

Toshiaki Hattori

Keyword(s):

Aqueous Solutions ◽

Protein Stability ◽

Time Domain ◽

Protein Solubility ◽

Hydration Water ◽

Hofmeister Series ◽

Terahertz Time Domain Spectroscopy ◽

Salt Effects ◽

Time Domain Spectroscopy ◽

Insight Into

The addition of salts into protein aqueous solutions causes changes in protein solubility and stability, the ability of which is known to be ordered in the Hofmeister series.

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