Characteristic 1H Chemical Shifts of Silk Fibroins Determined by 1H CRAMPS NMR
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- 作者：Hideaki Kimura ; Satoshi Kishi ; Akira Shoji ; Hisashi Sugisawa ; and Kenzo Deguchi
- 刊名：Macromolecules
- 出版年：2000
- 出版时间：December 26, 2000
- 年：2000
- 卷：33
- 期：26
- 页码：9682 - 9687
- 全文大小：77K
- 年卷期：v.33,no.26(December 26, 2000)
- ISSN：1520-5835
文摘
CRAMPS NMR of 1H was used for the structural analysis of some natural silk fibroinssuch as Tussah Antheraea pernyi and Bombyx mori in the solid state. We were able to resolve all expected1H NMR resonances. When tied to the resolution of 13C NMR via 2D 1H-13C HETCOR experiments,overlapping proton resonance under CRAMPS are able to be further resolved. The simplified 1H signalsof these natural proteins could be successfully assigned on the basis of the conformation-dependent 1Hchemical shifts of model polypeptides. The 1H chemical shift of the H
signals of Tussah A. pernyi fibroinadopting an -helix conformation (4.0 ppm) agrees with that of -helical poly(L-alanine) (3.9 ppm) towithin ±0.1 ppm. A well-defined poly(L-alanylglycine), [Ala-Gly]12, was used as a model polypeptide of B.mori silk fibroin. The 1H CRAMPS spectra of B. mori fibroins adopting the silk I or silk II form weresimilar to those of [Ala-Gly]12 adopting a corresponding conformation. The H chemical shifts of the silkI fibroin were 3.9 ppm (singletlike) whereas those of the silk II fibroin exhibited peaks at 5.0 and 3.9ppm. Further, we found that the 1H chemical shift of side chains in silk I was downfield by 0.4 ppmcompared with that in silk II. Thus, it is possible to assign the 1H CRAMPS NMR spectra of naturalproteins such as silk fibroins using model polypeptides of known structure as references.
signals of Tussah A. pernyi fibroinadopting an -helix conformation (4.0 ppm) agrees with that of -helical poly(L-alanine) (3.9 ppm) towithin ±0.1 ppm. A well-defined poly(L-alanylglycine), [Ala-Gly]12, was used as a model polypeptide of B.mori silk fibroin. The 1H CRAMPS spectra of B. mori fibroins adopting the silk I or silk II form weresimilar to those of [Ala-Gly]12 adopting a corresponding conformation. The H chemical shifts of the silkI fibroin were 3.9 ppm (singletlike) whereas those of the silk II fibroin exhibited peaks at 5.0 and 3.9ppm. Further, we found that the 1H chemical shift of side chains in silk I was downfield by 0.4 ppmcompared with that in silk II. Thus, it is possible to assign the 1H CRAMPS NMR spectra of naturalproteins such as silk fibroins using model polypeptides of known structure as references.