Applications of terahertz spectroscopy in biosystems

2007-12-03
Plusquellic, David F.
SİEGRİST, Karen
Heilweil, Edwin J.
Esentürk, Okan
Terahertz (THz) spectroscopic investigations of condensed-phase biological samples are reviewed ranging from the simple crystalline forms of amino acids, carbohydrates and polypeptides to the more complex aqueous forms of small proteins, DNA and RNA. Vibrationally resolved studies of crystalline samples have revealed the exquisite sensitivity of THz modes to crystalline order, temperature, conformational form, peptide sequence and local solvate environment and have given unprecedented measures of the binding force constants and anharmonic character of the force fields, properties necessary to improve predictability but not readily obtainable using any other method. These studies have provided benchmark vibrational data on extended periodic structures for direct comparisons with classical (CHARMm) and quantum chemical (density functional theory) theories. For the larger amorphous and/or aqueous phase samples, the THz modes form a continuum-like absorption that arises because of the full accessibility to conformational space and/or the rapid time scale for inter-conversion in these environments. Despite severe absorption by liquid water, detailed investigations have uncovered the photo- and hydration-induced conformational flexibility of proteins, the solvent shell depth of the water/biomolecule boundary layers and the solvent reorientation dynamics occurring in these interfacial layers that occur on sub-picosecond time scales. As such, THz spectroscopy has enhanced and extended the accessibility to intermolecular forces, length- and timescales important in biological structure and activity.
CHEMPHYSCHEM

Suggestions

Dielectric Properties of Ethanol and Gasoline Mixtures by Terahertz Spectroscopy and an Effective Method for Determination of Ethanol Content of Gasoline
ARIK, Enis; Altan, Hakan; Esentürk, Okan (American Chemical Society (ACS), 2014-05-01)
Investigation of frequency dependent permittivity of mixture solutions provides information on the role of intermolecular interactions on relaxation processes of solvent and solute molecules. In this study the dielectric properties of ethanol/gasoline mixtures in the terahertz spectral region are investigated. Frequency dependent absorption coefficients, refractive indices, and complex permittivities of pure ethanol and gasoline, and their mixtures at varying ethanol volume percentages (v/v %) are reported....
Active carbon/graphene hydrogel nanocomposites as a symmetric device for supercapacitors
ATEŞ, MURAT; Cinar, Damla; Caliskan, Sinan; GEÇGEL, ÜNAL; ÜNER, OSMAN; BAYRAK, YÜKSEL; Candan, Idris (Informa UK Limited, 2016-01-01)
Activated carbons (ACs) are successfully synthesized from Elaeagnus grain by a simple chemical synthesis methodology and demonstrated as novel, suitable supercapacitor electrode materials for graphene hydrogel (GH)/AC nanocomposites. GH/AC nanocomposites are synthesized via hydrothermal process at temperature of 180 degrees C. The low-temperature thermal exfoliation approach is convenient for mass production of graphene hydrogel (GH) at low cost and it can be used as electrode material for energy storage ap...
Investigation of biologically important small molecules: quantum chemical and molecular dynamics calculations
Tekin, Emine Deniz; Erkoç, Şakir; Department of Physics (2010)
In this thesis, six small molecules (S-allylcysteine, S-allyl mercaptocysteine, allicin, methyl propyl disulfide, allyl methyl sulfide and dipropylsulfide) that are found in garlic and onion, and are known to be beneficial for human health were studied using molecular mechanics, semi-empirical methods, ab-initio (Restricted Hartree Fock), and density functional theory. Using the same methods, a synthetic pyrethroid pesticide molecule, called cyfluthrin, was also studied. Structural, vibrational and electron...
Excitation Localization/Delocalization Isomerism in a Strongly Coupled Covalent Dimer of 1,3-Diphenylisobenzofuran
Schrauben, Joel N.; Akdağ, Akın; Wen, Jin; Havlas, Zdenek; Ryerson, Joseph L.; Smith, Millie B.; Michl, Josef; Johnson, Justin C. (American Chemical Society (ACS), 2016-05-26)
Two isomers of both the lowest excited singlet (S-1) and triplet (T-1) states of the directly para, para'-connected covalent dimer of the singlet-fission chromophore 1,3-diphenylisobenzofuran have been observed. In one isomer, excitation is delocalized over both halves of the dimer, and in the other, it is localized on one or the other half. For a covalent dimer in solution, such "excitation isomerism" is extremely rare. The vibrationally relaxed isomers do not interconvert, and their photophysical properti...
Mechanistic Insights into the Reaction of N-Propargylated Pyrrole- and Indole-Carbaldehyde with Ammonia, Alkyl Amines, and Branched Amines: A Synthetic and Theoretical Investigation
Sari, Ozlem; Seybek, Ali Fatih; Kaya, Serap; Menges, Nurettin; ERDEM, SAFİYE; BALCI, METİN (Wiley, 2019-09-01)
The reaction of pyrrole- and indole-carbaldehydes having a propargyl group attached to the nitrogen atom with various amines was studied. The reaction with ammonia formed pyrrolo[1,2-a]pyrazine and pyrazino[1,2-a]indole while the reaction with alkylamines such as methyl, ethyl, hexyl, and benzylamines formed the corresponding pyrazinone derivatives. Unexpectedly, the reaction with allylamine and propargylamine formed pyrazine derivatives in which the allyl and propargyl groups were removed from the molecule...
Citation Formats
D. F. Plusquellic, K. SİEGRİST, E. J. Heilweil, and O. Esentürk, “Applications of terahertz spectroscopy in biosystems,” CHEMPHYSCHEM, pp. 2412–2431, 2007, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/45597.