Noncovalent intermolecular forces in polycrystalline and amorphous saccharides in the far infrared

Walther, Markus; Fischer, Bernd; Jepsen, Peter Uhd

doi:10.1016/s0301-0104(03)00031-4

Cited by 329 publications

(262 citation statements)

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“…In many cases, however, asymmetrically distorted absorption bands are observed affecting the reported line widths, peak positions, and absorption strengths. [1][2][3]7,8 In this letter, we show that dispersion-induced scattering on the inhomogeneities in the sample, a behavior known as the Christiansen effect, 9 is responsible for these spectral distortions. Based on the knowledge of the refractive indices of sample and host medium, a recipe is presented which numerically eliminates the scattering contribution from the terahertz absorption spectrum.…”

Section: The Christiansen Effect In Terahertz Time-domain Spectra Of mentioning

confidence: 82%

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The Christiansen effect in terahertz time-domain spectra of coarse-grained powders

Fränz

Fischer

Walther

2008

Applied Physics Letters

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Spectral distortions are commonly observed in terahertz transmission spectra of ground substances immersed in a transparent host medium. This effect originates from scattering due to the index contrast between the grains and diluent. A phenomenological expression quantitatively accounts for the scattering induced attenuation and the phase delay experienced by the electric field transmitted through the sample. Based on the knowledge of the refractive indices of the sample and the host material, we present a procedure to eliminate the scattering contribution from the absorption spectra.

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Section: The Christiansen Effect In Terahertz Time-domain Spectra Of mentioning

confidence: 82%

“…[12][13][14] This effect, first described by Christiansen,9 has been occasionally observed in terahertz TDS measurements, [1][2][3]7,8 however, was not further considered. As indicated in the inset of Fig.…”

Section: The Christiansen Effect In Terahertz Time-domain Spectra Of mentioning

confidence: 97%

The Christiansen effect in terahertz time-domain spectra of coarse-grained powders

Fränz

Fischer

Walther

2008

Applied Physics Letters

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“…The sharp orientation-dependent resonances may originate from either intramolecular motions or crystal lattice vibrations, phonons. Typical molecular crystals (such as sucrose) with basis group molecular weights of B100 Da have lattice phonons in the 10-100 cm À 1 range [29][30][31] . The lattice phonon frequency will scale inversely with the square root of the mass of the lattice basis, suggesting the lattice phonons for the 14-kDa molecular weight CEWL basis crystals are over an order of magnitude smaller, with frequencies less than 10 cm À 1 .…”

Section: Normal Mode Analysismentioning

confidence: 99%

Optical measurements of long-range protein vibrations

et al. 2014

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Protein biological function depends on structural flexibility and change. From cellular communication through membrane ion channels to oxygen uptake and delivery by haemoglobin, structural changes are critical. It has been suggested that vibrations that extend through the protein play a crucial role in controlling these structural changes. While nature may utilize such long-range vibrations for optimization of biological processes, bench-top characterization of these extended structural motions for engineered biochemistry has been elusive. Here we show the first optical observation of long-range protein vibrational modes. This is achieved by orientation-sensitive terahertz near-field microscopy measurements of chicken egg white lysozyme single crystals. Underdamped modes are found to exist for frequencies 410 cm À 1 . The existence of these persisting motions indicates that damping and intermode coupling are weaker than previously assumed. The methodology developed permits protein engineering based on dynamical network optimization.

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“…3a which shows the absorption for a single lysozyme molecule for the polarization parallel to the HEWL static dipole λ‖p 0 =λ‖ (shown in blue), and for the perpendicular polarization λ ⊥ p 0 = λ ⊥ (shown in red). A 4 cm −1 linewidth is assumed for all frequencies, consistent with linewidth measurements of molecular crystals at room temperature (Korter et al 2006;Kröll et al 2007;Singh et al 2012;Walther et al 2003). As seen in Fig.…”

Section: Terahertz Tds Protein Measurementsmentioning

confidence: 53%

Terahertz optical measurements of correlated motions with possible allosteric function

Niessen

Markelz

2015

Biophys Rev

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A suggested mechanism for allosteric response is the distortion of the energy landscape with agonist binding changing the protein structure's access to functional configurations. Intramolecular vibrations are indicative of the energy landscape and may have trajectories that enable functional conformational change. Here, we discuss the development of an optical method to measure the intramolecular vibrations in proteins, namely, crystal anisotropy terahertz microscopy, and the various approaches which can be used to identify the spectral data with specific structural motions.

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Noncovalent intermolecular forces in polycrystalline and amorphous saccharides in the far infrared

Cited by 329 publications

References 29 publications

The Christiansen effect in terahertz time-domain spectra of coarse-grained powders

The Christiansen effect in terahertz time-domain spectra of coarse-grained powders

Optical measurements of long-range protein vibrations

Terahertz optical measurements of correlated motions with possible allosteric function

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