Raman Spectroscopic Investigation of the Denaturation Process of Silk Fibroin
- 1 September 1989
- journal article
- research article
- Published by SAGE Publications in Applied Spectroscopy
- Vol. 43 (7), 1269-1272
- https://doi.org/10.1366/0003702894203525
Abstract
The mechanical denaturation process of silk fibroin is examined by Raman spectroscopy. The fresh silk fibroins from the middle gland of mature silkworms are drawn to various ratios on a tensile tester ( R = ldrawn/ linitial, where l is length) and their conformations are measured with Raman spectroscopy. Undrawn silk fibroin is mainly in the random coil structure with some α-helical conformation, the characteristic bands appearing at 1252 and 1660 (random coil) and at 942, 1106, and 1270 cm−1 (α-helix). When the samples are drawn up to R = 4 at an extension rate of 500 mm/min, two peaks at 1233 cm−1 (the amide III band) and 1085 cm−1 appear; it is shown that the β-sheet conformation is then formed. With an increase in drawing ratios, the intensities of these β-sheet bands increase and those of the random coil and α-helical bands decrease gradually. These changes indicate that, under the action of stress, the conformation of fibroin is altered from random coil and α-helix to β-sheet structures. This result is quite similar to the results achieved by the spinning of the silkworm. The effect of the water content in liquid silk on this conformational transition process is revealed and discussed.Keywords
This publication has 13 references indexed in Scilit:
- Raman Spectra and Conformations of Copolypeptides Containing Glycine, L-Alanine, and L-Phenylalanine ResiduesPolymer Journal, 1986
- Conformational characterization of Bombyx mori silk fibroin in the solid state by high-frequency carbon-13 cross polarization-magic angle spinning NMR, x-ray diffraction, and infrared spectroscopyMacromolecules, 1985
- The physico-chemical properties of silk fibers and the fiber spinning processCellular and Molecular Life Sciences, 1983
- Mechanical denaturation of high polymers in solutions. XXXVI. Flow-induced crystallization of Bombyx Mori L. silk fibroin from the aqueous solution under a steady-state flowJournal of Macromolecular Science, Part B, 1982
- The chemical structure and the crystalline structures of Bombyx mori silk fibroinBiochimie, 1979
- Laser Raman Scattering as a Probe of Protein StructureAnnual Review of Biochemistry, 1977
- Laser raman investigation of the conformation of human immunoglobulin GBiochimica et Biophysica Acta (BBA) - Protein Structure, 1976
- Raman spectroscopic study of mechanically deformed poly‐L‐alaninePeptide Science, 1974
- Laser Raman studies of conformational variations of poly‐L‐lysinePeptide Science, 1973
- X-ray and U.-V. spectrographic investigations of fibrous and globular modifications of silk fibroinDiscussions of the Faraday Society, 1951