终端功能组对聚二烯II结构稳定性的影响:一项综合实验和理论研究
Michael Kuemin1, Sabine Schweizer, Christian Ochsenfeld
1Department of Chemistry, University of Basel, St. Johanns-Ring 19, CH-4056 Basel, Switzerland.
Journal of the American Chemical Society
|October 2, 2009
概括
终端功能组显著影响聚烯螺旋的稳定性. 充电的端子破坏了聚二烯II (PPII) 螺旋的稳定,有利于聚二烯I (PPI) 螺旋,而封闭的端子稳定了PPII. 静电相互作用支配着这些形状偏好.
科学领域:
- 生物物理学的生物物理.
- 计算化学的计算化学
- 频谱学是一种光谱学.
背景情况:
- 聚二烯 (PPII) 螺旋是和蛋白质中普遍存在的形状.
- 了解稳定或破坏PPII螺旋的因素对于预测的结构和功能至关重要.
- 具有不同终端修饰的寡聚氨酸作为研究这些因素的模型系统.
研究的目的:
- 在实验和理论上检查聚二烯II (PPII) 螺旋体的结构稳定性.
- 为了确定充电和封闭端子对PPII与聚烯I (PPI) 螺旋相对稳定的影响.
- 阐明静电相互作用在控制PPII螺旋稳定性的作用.
主要方法:
- 循环二元化 (CD) 光谱法用于研究形状变化.
- 开始的量子化学计算 (MP2) 来计算PPI和PPII螺旋之间的能量差异.
- 对终端组和胺双极之间的电荷双极相互作用进行分析.
主要成果:
- 带正电荷的N端和负电荷的C端破坏了PPII螺旋的稳定,有利于PPI螺旋.
- 顶端稳定了PPII螺旋在PPI螺旋上.
- 量子化学计算证实了实验发现,将稳定性差异归因于静电相互作用,特别是PPI螺旋中更强的电荷双极相互作用.
结论:
- 终端功能组在决定寡头蛋白的结构稳定性方面发挥着至关重要的作用.
- 静电相互作用,特别是电荷双极相互作用,是PPI和PPII螺旋之间观察到的稳定性差异的主要驱动因素.
- 取决于pH值的研究证实了这些效应的静电性质,通过改变质子状态来控制螺旋稳定性的手段.
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