Polarized Raman scattering from a helical biopolymer

Wilser, Walter T.; Fitchen, D. B.

doi:10.1063/1.430476

Cited by 22 publications

(27 citation statements)

References 6 publications

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“…Interestingly, our calculation is consistent with polarized Raman measurements by Wilser & Fitchen (1975) on an oriented film of a-helical poly-g-benzyl-L-glutamate (PBLG), which yielded an experimental value of I cc /I bb = 3.7(20.5). Recent Raman microscope measurements on oriented a-helical PBLG establish that I cc /I bb is approximately 3.5 (unpublished results of M. Tsuboi and T. Ikeda).…”

supporting

confidence: 85%

Subunit Orientation in the Filamentous VirusFf(fd, f1, M13)

Overman

Tsuboi

Thomas

1996

Journal of Molecular Biology

108

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supporting

confidence: 85%

Subunit Orientation in the Filamentous VirusFf(fd, f1, M13)

Overman

Tsuboi

Thomas

1996

Journal of Molecular Biology

108

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“…[25][26][27][28] The peak areas of the amide I, amide II, NH stretching, and the carbonyl ester stretching band R were determined by peak deconvolution. Two grafted PBLG films before ͑SA-UW͒ and after ͑SA-W͒ the cleaning treatment, a spin-cast PBLG film ͑SC͒, and a Langmuir-Blodgett-Kuhn film of a waterspreadable copolymer of ͑␥-octadecyl 30%, ␥-methyl 70%͒ L-glutamate ͑LB-PG͒ were included in the analysis.…”

Section: Gir-ftir Measurementsmentioning

confidence: 99%

Quadrupolar and polar anisotropy in end-grafted α-helical poly(γ-benzyl-L-glutamate) on solid substrates

Frank

Forstmann

Johannsmann

1999

The Journal of Chemical Physics

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Electric field induced structural change for poly(vinylidene fluoride-co-trifluoroethylene) ultrathin films studied by scanning Maxwell stress microscope Using grazing incidence reflectance Fourier transform infrared spectroscopy ͑GIR-FTIR͒ and electro-optic ͑EO͒ measurements, we have determined the degree of quadrupolar and polar anisotropy in end-grafted ␣-helical poly͑␥-benzyl-L-glutamate͒ ͑PBLG͒ chains. The results are compared to data obtained on spin-cast and on Langmuir-Blodgett-Kuhn ͑LBK͒ films. End-grafted films were prepared by a vapor-deposition-polymerization ͑VDP͒ scheme and have thicknesses of up to 70 nm. The quadrupolar order of VDP films, as estimated by the nematic order parameter S, is higher than in spin-cast and LBK films. This result indicates a preferentially perpendicular alignment of PBLG chains in VDP films. Furthermore, after the removal of the physisorbed chains from the grafted films by intensive washing with solvent, the quadrupolar order is lowered while the polar order increases significantly, suggesting that the physisorbed chains might form anti-parallel pairs with the surface-grafted chains.

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“…Widely used vibrational spectroscopic techniques include polarized Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR),14–28 polarized Raman spectroscopy,19,20,29–38 and, recently, Sum Frequency Generation (SFG) vibrational spectroscopy 39–55. The orientation analyses of helical structures using these techniques require knowledge of the detailed structure of the helices at the atomic level.…”

Section: Introductionmentioning

confidence: 99%

Orientation Determination of Protein Helical Secondary Structures Using Linear and Nonlinear Vibrational Spectroscopy

et al. 2009

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In this paper, we systematically presented the orientation determination of protein helical secondary structures using vibrational spectroscopic methods, particularly the nonlinear Sum Frequency Generation (SFG) vibrational spectroscopy, along with linear vibrational spectroscopic techniques such as infrared spectroscopy and Raman scattering. SFG amide I signals can be collected using different polarization combinations of the input laser beams and output signal beam to measure the second order nonlinear optical susceptibility components of the helical amide I modes, which are related to their molecular hyperpolarizability elements through the orientation distribution of these helices. The molecular hyperpolarizability elements of amide I modes of a helix can be calculated based on the infrared transition dipole moment and Raman polarizability tensor of the helix; these quantities are determined by using the bond additivity model to sum over the individual infrared dipole transition moments and Raman polarizability tensors, respectively, of the peptide units (or the amino acid residues). The computed overall infrared transition dipole moment and Raman polarizability tensor of a helix can be validated by experimental data using polarized infrared and polarized Raman spectroscopy on samples with well-aligned helical structures. From the deduced SFG hyperpolarizability elements and measured SFG second order nonlinear susceptibility components, orientation information regarding helical structures can be determined. Even though such orientation information can also be measured using polarized infrared or polarized Raman amide I signals, SFG has a much lower detection limit, which can be used to study the orientation of a helix when its surface coverage is much lower than a monolayer. In addition, the combination of different vibrational spectroscopic techniques, e.g., SFG and Attenuated Total Reflectance – Fourier Transform Infrared spectroscopy, provides more measured parameters for orientation determination, aiding in the deduction of more complicated orientation distributions. In this paper, we discussed two types of helices: the α-helix and 3–10 helix. However, the orientation determination method presented here is general, and thus can be applied to study other helices as well. The calculations of SFG amide I hyperpolarizability components for α-helical and 3–10 helical structures with different chain lengths have also been performed. It was found that when the helices reach a certain length, the number of peptide units in the helix should not alter the data analysis substantially. It was shown in the calculation, however, that when the helix chain is short, the SFG hyperpolarizability component ratios can vary substantially when the chain length is changed. Because 3–10 helical structures can be quite short in proteins, the orientation determination for a short 3–10 helix needs to take into account the number of peptide units in the helix.

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Polarized Raman scattering from a helical biopolymer

Cited by 22 publications

References 6 publications

Subunit Orientation in the Filamentous VirusFf(fd, f1, M13)

Subunit Orientation in the Filamentous VirusFf(fd, f1, M13)

Quadrupolar and polar anisotropy in end-grafted α-helical poly(γ-benzyl-L-glutamate) on solid substrates

Orientation Determination of Protein Helical Secondary Structures Using Linear and Nonlinear Vibrational Spectroscopy

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