The Raman analysis of films cast from dissolved feather keratin

Church, Jeffrey S.; Poole, Andrew J.; Woodhead, Andrea L.

doi:10.1016/j.vibspec.2010.02.011

Cited by 23 publications

(23 citation statements)

References 26 publications

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“…To test this hypothesis, dark feathers from study skins of five extant taxa (Phalacrocorax auritus, Branta canadensis, Fratercula arctica, Himantopus mexicanus and Larus atricilla), were placed between two glass microscope slides. A 10% solution of Na 2 S (Acros, Morris Plains, NJ), which dissolves feather keratin by breaking disulfide bridges of cystine [11], was injected between the slides to remove the keratin matrix surrounding the melanosomes. Melanin does not contain disulfide bridges, and is a tough and insoluble polymer [12]; thus, it should be unaffected by the treatment, despite the complete degradation of keratin.…”

Section: Methodsmentioning

confidence: 99%

Melanin Concentration Gradients in Modern and Fossil Feathers

et al. 2013

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In birds and feathered non-avian dinosaurs, within-feather pigmentation patterns range from discrete spots and stripes to more subtle patterns, but the latter remain largely unstudied. A ∼55 million year old fossil contour feather with a dark distal tip grading into a lighter base was recovered from the Fur Formation in Denmark. SEM and synchrotron-based trace metal mapping confirmed that this gradient was caused by differential concentration of melanin. To assess the potential ecological and phylogenetic prevalence of this pattern, we evaluated 321 modern samples from 18 orders within Aves. We observed that the pattern was found most frequently in distantly related groups that share aquatic ecologies (e.g. waterfowl Anseriformes, penguins Sphenisciformes), suggesting a potential adaptive function with ancient origins.

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Section: Methodsmentioning

confidence: 99%

Melanin Concentration Gradients in Modern and Fossil Feathers

et al. 2013

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“…Fibers were orientated with respect to the laser polarization using a rotating stage. The system geometry and nomenclature used to describe the four unique polarized spectra are described elsewhere . Briefly, the fiber is in the xy plane with the draw axis coincident with the x ‐axis.…”

Section: Methodsmentioning

confidence: 99%

Continuous Production of Flexible Fibers from Transgenically Produced Honeybee Silk Proteins

Poole

Church

Woodhead

et al. 2013

Macromolecular Bioscience

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Flexible and solvent stable fibers are produced after concentrated recombinant honeybee protein solutions are extruded into a methanol bath, dried, drawn in aqueous methanol, then covalently cross-linked using dry heat. Proteins in solution are predominantly coiled coil. Significant levels of non-orientated ß-sheets form during drying or after coagulation in aqueous methanol. Drawing generally aligns the coiled coil component parallel with the fibre axis and ß-sheet component perpendicular to the fiber axis. The fibres are readily handled, stable in the strong protein denaturants, urea and guanidinium, and suitable for a range of applications such as weaving and knitting.

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“…79 The procedure for determining the orientation of chemical groups based on polarized Raman spectroscopy has been previously reported. 35,80,81 Briefly, this method is based on acquiring four polarized Raman spectra (I ZZ , I ZX , I XX , and I XZ ) in the backscattering configuration 35 (see the Supporting Information).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Structural Organization of Insulin Fibrils Based on Polarized Raman Spectroscopy: Evaluation of Existing Models

Sereda

Sawaya²,

Lednev

2015

J. Am. Chem. Soc.

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Many different proteins undergo misfolding and self-assemble into amyloid fibrils, resulting in a range of neurodegenerative diseases. The limitations of conventional methods of structural biology for fibril characterization have led to the use of polarized Raman spectroscopy for obtaining quantitative structural information regarding the organization of amyloid fibrils. Herein, we report the orientation of selected chemical groups and secondary structure elements in aligned insulin fibrils, including β-sheets, which possess a high level of orientation in the cross-β core, and α-helices in the disordered portions of the fibrils. Strong orientation of disulfide bonds in amyloid fibrils was also revealed, indicating their association with the fibril core. The determined orientation of chemical groups provides strong constraints for modeling the overall structure of amyloid fibrils, including the core and disordered parts. The developed methodology allows for the validation of structural models proposed in the literature for amyloid fibrils. Specifically, the polarized Raman data obtained herein strongly agreed with two insulin fibril models (Jiménez et al., Proc. Natl. Acad. Sci. U. S. A. 2002, 99, 9196-9201 and Ivanova et al., Proc. Natl. Acad. Sci. U. S. A. 2009, 106, 18990-18995) yet revealed significant qualitative and quantitative differences. This work demonstrates the great potential of polarized Raman spectroscopy for structural characterization of anisotropic biological species.

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The Raman analysis of films cast from dissolved feather keratin

Cited by 23 publications

References 26 publications

Melanin Concentration Gradients in Modern and Fossil Feathers

Melanin Concentration Gradients in Modern and Fossil Feathers

Continuous Production of Flexible Fibers from Transgenically Produced Honeybee Silk Proteins

Structural Organization of Insulin Fibrils Based on Polarized Raman Spectroscopy: Evaluation of Existing Models

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