Infrared and Raman microscopy of fowl feather barb

Tsuboi, Masamichi; Kaneuchi, Fumiko; Ikeda, Teruki; Akahane, Kiso

doi:10.1139/v91-257

Cited by 28 publications

(30 citation statements)

References 4 publications

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“…For β-sheet structures, the principle x-axis of Tsuboi’s polarizability tensor is found to be significantly more in line with the C=O bond; this tilt angle is only 22 degrees (instead of 34.5 degrees in α-helical structures) 95. This refinement was made by adjusting this tilt angle so that the Raman intensity ratio

\frac{I_{c c}}{I_{b b}}

matches the experimental observations on Bombyx mori silk (

\frac{I_{c c}}{I_{b b}} = 0.304

), Nephila edulis spidroin (

\frac{I_{c c}}{I_{b b}} = 0.406

), S. c. ricini fibroin silk (

\frac{I_{c c}}{I_{b b}} = 0.257

), and fowl feather barb (

\frac{I_{c c}}{I_{b b}} = 0.429

) 94,95,97. For the β-sheet, the polarizability tensor can be written in the given molecular frame as defined in Figure 2.…”

Section: Orientation Determination Of β-Sheetmentioning

confidence: 99%

Orientation Determination of Interfacial β-Sheet Structures in Situ

2010

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Structural information such as orientations of interfacial proteins and peptides is important for understanding properties and functions of such biological molecules, which play crucial roles in biological applications and processes such as antimicrobial selectivity, membrane protein activity, biocompatibility, and biosensing performance. The α-helical and β-sheet structures are the most widely encountered secondary structures in peptides and proteins. In this paper, for the first time, a method to quantify the orientation of the interfacial β-sheet structure using a combined Attenuated Total Reflectance Fourier Transformation Infrared Spectroscopic (ATR-FTIR) and Sum Frequency Generation (SFG) vibrational spectroscopic study was developed. As an illustration of the methodology, the orientation of tachyplesin I, a 17-amino acid peptide with an anti-parallel β-sheet, adsorbed to polymer surfaces as well as associated with a lipid bilayer was determined using the regular and chiral SFG spectra, together with polarized ATR-FTIR amide I signals. Both the tilt angle (θ) and the twist angle (ψ) of the β-sheet at interfaces are determined. The developed method in this paper can be used to obtain in situ structural information of β-sheet components in complex molecules. The combination of this method and the existing methodology that is currently used to investigate α-helical structures will greatly broaden the application of optical spectroscopy in physical chemistry, biochemistry, biophysics, and structural biology.

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\frac{I_{c c}}{I_{b b}}

matches the experimental observations on Bombyx mori silk (

\frac{I_{c c}}{I_{b b}} = 0.304

), Nephila edulis spidroin (

\frac{I_{c c}}{I_{b b}} = 0.406

), S. c. ricini fibroin silk (

\frac{I_{c c}}{I_{b b}} = 0.257

), and fowl feather barb (

\frac{I_{c c}}{I_{b b}} = 0.429

) 94,95,97. For the β-sheet, the polarizability tensor can be written in the given molecular frame as defined in Figure 2.…”

Section: Orientation Determination Of β-Sheetmentioning

confidence: 99%

Orientation Determination of Interfacial β-Sheet Structures in Situ

2010

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“…17 (Note that in order to achieve the experimental value of I cc /I bb D 0.304 for B. mori silk fibroin using the above tensors, it is required that the crystallite or fibrous sample be tilted by as much as 30°from the c-axis, which is not compatible with the experimental design and data collection. 18 -21 ) Thus, we conclude that the foregoing first approximation to thě -sheet tensor requires further modification, as proposed in the following text.…”

Section: Calculation Of the Amide I Raman Tensor For The Antiparallelmentioning

confidence: 99%

Determination of the amide I Raman tensor for the antiparallel β‐sheet: application to silkworm and spider silks

Tsuboi

Kubo²,

Akahane

et al. 2006

J Raman Spectroscopy

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The amide I Raman tensor corresponding to the antiparallel b-sheet structure in proteins has been determined by polarized Raman microspectroscopy of fowl feather rachis using polarized Raman spectra excited in the near-infrared (785 nm). For a Raman tensor principal axis system (XYZ), in which X is perpendicular to the plane of the pleated b-sheet, Y is in the plane of the sheet and perpendicular to the direction of the polypeptide chain, and Z is parallel to the direction of the polypeptide chain, the principal tensor components (a XX , a YY , a ZZ ) are found to satisfy the following relationships: R 1 ≡ a XX /a ZZ = 0.32 and R 2 ≡ a YY /a ZZ = 3.48. With this Raman tensor determination, we show that semiquantitative estimates of the total antiparallel b-sheet content in b-rich proteins can be extracted from polarized Raman intensity measurements on the amide I marker of the b-sheet occurring near 1664 cm −1 . We demonstrate this approach for the b-rich silk proteins of the silkworm and spider. INTRODUCTIONThe antiparallel chain, pleated-sheet conformation (ˇ-sheet) is a fundamental structural component of native proteins. 1 The silk of both silkworms and spiders and the rachis keratins of fowl feather barbs are examples of native proteins in which the antiparallelˇ-sheet is the major structural element. 2 A key property of theˇ-sheet structure in both silk and feathers is a high degree of polypeptide chain orientation. Thě -sheet conformation is also prevalent in nonnative and misfolded proteins and has been implicated in polypeptide † Presented as part of a commemorative issue for Wolfgang Kiefer on the occasion of his 65th birthday.

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“…The pioneers in this field are Tsuboi et al2–6 They have been attempting to systematically measure the polarizability tensor of vibrations of interest in biological molecules, such as the amide I vibration of proteins and the tyrosine ring breathing mode. The techniques they have developed are summarized in a recent review 6.…”

Section: Introductionmentioning

confidence: 99%

Keratin orientation in wool and feathers by polarized Raman spectroscopy

et al. 2000

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Good quality polarized Raman spectra of a single wool fiber and an intact feather barbule are presented. The intensity ratio of the α‐helix component of the amide I band measured parallel and perpendicular to the wool fiber axis was 0.39 ± 0.05. This is consistent with theoretical predictions based on orientational calculations using the normal Raman polarizability tensor for an α‐helical amide I band where the protein strands are aligned roughly parallel with the fiber axis. However, the depolarized spectral intensity of the α‐helix mode was greater than expected. For the feather barbule, despite high quality spectra, a unique orientation of the β‐sheet structure could not be determined using the Raman intensity ratios of the amide I band alone. Using previously developed methods, the protein chains were found to be oriented between 60 and 90° from the long axis of the barbule compared to an angle of 51° calculated from polarized IR spectra of the same barbule. The Raman tensor methods for the determination of protein orientation in these fibers was found to be constrained by the complexity of the materials and the limitations of the band fitting methods used to apportion the intensity among the various vibrational modes of their spectra. Other advantages and limitations of polarized Raman microscopic methods of structural determination are discussed. © 2000 John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 57: 19–28, 2000

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Infrared and Raman microscopy of fowl feather barb

Cited by 28 publications

References 4 publications

Orientation Determination of Interfacial β-Sheet Structures in Situ

Orientation Determination of Interfacial β-Sheet Structures in Situ

Determination of the amide I Raman tensor for the antiparallel β‐sheet: application to silkworm and spider silks

Keratin orientation in wool and feathers by polarized Raman spectroscopy

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