Effect of pH and copper(II) on the conformation transitions of silk fibroin based on EPR, NMR, and Raman spectroscopy
文献类型：期刊论文
| 作者 | Zong, XH; Zhou, P; Shao, ZZ; Chen, SM; Chen, X; Hu, BW; Deng, F; Yao, WH |
| 刊名 | BIOCHEMISTRY
 |
| 出版日期 | 2004-09-28 |
| 卷号 | 43期号:38页码:11932-11941 |
| 英文摘要 | Much attention has been paid to the natural mechanism of silkworm spinning due to the impressive mechanical properties of the natural fibers. Our results in the present work show that the fractional changes of the conformational components in regenerated silk fibroin (SF) extracted from Bombyx mori fibers is remarkably pH- and Cu(II)-dependent as demonstrated by Cu(II) EPR,C-13 NMR, and Raman spectroscopy. Cu(II) coordination atoms in SF are changed from four nitrogens to two nitrogens and two oxygens as well as to one nitrogen and three oxygens when the pH is lowered from 8.0 to 4.0. The addition of a given amount of Cu(II) into a SF solution could induce efficiently the SF conformational fractional change from silk I, a soluble helical conformation, to silk II, an insoluble beta-sheet conformation. This behavior is strikingly similar to that seen in prion protein and amyloid beta-peptide. On the basis of the similarity in the relevant sequence in SF to the octapeptide PHGGGWGQ in PrP, we suggest that at basic and neutral pH polypeptide AHGGYSGY in SF may form a 1:1 complex with Cu(II) by coordination of imidazole N-pi of His together with two deprotonated main-chain nitrogens from two glycine residues and one nitrogen or oxygen from serine. Such a type of coordination may make the interaction between two adjacent beta-form polypeptide chains more difficult, thereby leading to an amorphous structure. Under weakly acidic conditions, however, Cu(II)-amide linkages may be broken and Cu(II) may switch to bind two N-tau from two histidines in adjacent peptide chains, forming an intermolecular His(N-tau)-Cu(II)-His(N-tau) bridge. This type of coordination may induce beta-sheet formation and aggregation, leading to a crystalline structure. |
| WOS标题词 | Science & Technology ; Life Sciences & Biomedicine |
| 类目[WOS] | Biochemistry & Molecular Biology |
| 研究领域[WOS] | Biochemistry & Molecular Biology |
| 关键词[WOS] | PARAMAGNETIC RESONANCE-SPECTRA ; ANGLE SPINNING METHOD ; C-13 CHEMICAL-SHIFTS ; BOMBYX-MORI SILKWORM ; MURINE PRION PROTEIN ; CU2+ BINDING-SITES ; C-TERMINAL DOMAIN ; SOLID-STATE C-13 ; STRUCTURAL IMPLICATIONS ; SECONDARY STRUCTURE |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000224032900002 |
| 公开日期 | 2015-07-28 |
| 源URL | [http://ir.wipm.ac.cn/handle/112942/4420]  |
| 专题 | 武汉物理与数学研究所_2011年以前论文发表（包括2011年） |
| 作者单位 | 1.Fudan Univ, Dept Macromol Sci, Key Lab Mol Engn Polymers, Shanghai 200433, Peoples R China 2.Fudan Univ, Analyt Measurement Ctr, Shanghai 200433, Peoples R China 3.Chinese Acad Sci, Wuhan Inst Phys & Math, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan 430071, Peoples R China |
| 推荐引用方式 GB/T 7714 | Zong, XH,Zhou, P,Shao, ZZ,et al. Effect of pH and copper(II) on the conformation transitions of silk fibroin based on EPR, NMR, and Raman spectroscopy[J]. BIOCHEMISTRY,2004,43(38):11932-11941. |
| APA | Zong, XH.,Zhou, P.,Shao, ZZ.,Chen, SM.,Chen, X.,...&Yao, WH.(2004).Effect of pH and copper(II) on the conformation transitions of silk fibroin based on EPR, NMR, and Raman spectroscopy.BIOCHEMISTRY,43(38),11932-11941. |
| MLA | Zong, XH,et al."Effect of pH and copper(II) on the conformation transitions of silk fibroin based on EPR, NMR, and Raman spectroscopy".BIOCHEMISTRY 43.38(2004):11932-11941. |
入库方式： OAI收割
来源：武汉物理与数学研究所
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