在水溶液中,基于氨酸的短可以形成3(10) -螺旋体而不是α-螺旋体
S M Miick1, G V Martinez, W R Fiori
1Department of Chemistry and Biochemistry, University of California, Santa Cruz 95064.
Nature
|October 15, 1992
概括
短的氨酸可以形成α-螺旋,但区分α-螺旋和3(10) -螺旋是具有挑战性的. 新的旋转标记技术显示,这些可能在溶液中采用3~10状螺旋结构.
科学领域:
- 生物物理化学 生物物理化学
- 结构生物学是结构生物学.
- 酸科学是一种科学.
背景情况:
- 短的素 (16 - 17 个残留物) 被认为在水溶液中形成阿尔法螺旋环.
- 标准的光谱学方法,如循环二重化 (CD) 和核磁共振 (NMR),无法区分α-螺旋和3(10) -螺旋.
- 3(10) -螺旋涉及i到i+3残留结合,与α-螺旋中的i到i+4结合不同.
研究的目的:
- 开发和应用新的方法来区分短的氨酸中的α-螺旋和3(10) -螺旋结构.
- 使用先进的光谱技术,研究以氨酸为基础的的二次结构偏好.
主要方法:
- 设计和合成单旋和双旋标记的氨酸类似物.
- 通过氨酸残留物将氧化物旋转标签纳入.
- 使用循环二极化 (CD),里埃变换红外光谱 (FTIR) 和电子自旋共振 (ESR) 谱学的分析.
主要成果:
- FTIR amide I' 频段的频率与阿尔法螺旋的典型频率有很大差异.
- 双重标记的ESR光谱显示侧链距离排名与α-螺旋形状不一致.
- 实验数据强烈暗示一个3(10) 螺旋结构.
结论:
- 该研究成功地区分了短的氨酸中的α-螺旋和3(10) -螺旋结构.
- 与多种光谱方法相结合的自旋标记为结构确定提供了一种强大的方法.
- 这些发现表明,短的氨酸在溶液中主要采用3 10状螺旋形状.
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