在5-tert-butylprolyl类型VIβ转中对体几何学的序列效应模仿β转
Liliane Halab1, William D Lubell
1Département de chimie, Université de Montréal, C. P. 6128, Succursale Centre Ville, Montréal, Québec, Canada H3C 3J7.
Journal of the American Chemical Society
|March 14, 2002
概括
序列显著影响回转几何. 结合三乙烯稳定了特定的β-转变形状,由堆叠相互作用和特定的氨基酸序列驱动.
科学领域:
- 类化学 类化学
- 结构生物学 结构生物学
- 有机化学 有机化学
背景情况:
- 体构成对生物功能至关重要.
- 众所周知,氨酸残留物会影响的二次结构,特别是β转.
- 了解控制形状的因素是设计新的关键.
研究的目的:
- 为了研究结合 (2S,5R) -5-tert-butylproline (5-(t) BuPro) 如何影响转几何.
- 阐明控制酸平衡的因素和VI型β转的稳定性.
- 探索氨基酸序列对含有5-(t) BuPro.t的的构造偏好的影响.
主要方法:
- 含有5-(t) BuPro. 的二和四类型的合成.
- 使用核磁共振 (NMR) 和循环二极化 (CD) 谱学进行形状分析.
- 进行X射线衍射研究以确定晶体结构并确认形状.
主要成果:
- 观察到高的cis-异构体种群,特别是由于pi-系统堆叠相互作用,由于proline的N-终端芳香残留物.
- 在四聚中 (在Xaa,芳香在Yaa,Ala或Lys在Zaa) 的特定序列产生了>80%的cis-同位素群.
- 具有高cis异构体含量的采用了VIa型β转变构造,通过光谱数据证实了这一点.
结论:
- 序列上下文在决定形和prolyl amide平衡方面发挥着至关重要的作用.
- 5-(t) BuPro通过特定的依赖序列的相互作用有效地稳定VIa型β转变.
- 虽然发针几何学被建议,但在研究的四类的水溶液中,强烈的分子内键并不明显.
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