质子转移引起的构造变化和在气相中设计的中的化
Motoya Kohtani1, Thaddeus C Jones, Rajagopalan Sudha
1Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA.
Journal of the American Chemical Society
|June 1, 2006
概括
由于质子转移,形状随温度变化而变化. 氨酸-氨酸-氨酸 (RAK) 和氨酸-氨酸-氨酸 (RAH) 呈现温度依赖的螺旋体-球体过渡和螺旋体化.
科学领域:
- 生物物理学的生物物理.
- 计算化学的计算化学
- 蛋白质科学 蛋白质科学
背景情况:
- 类是短链的氨基酸.
- 质子转移可以影响结构.
- 了解形状是蛋白质折叠的关键.
研究的目的:
- 为了研究质子氨酸-氨酸-氨酸-氨酸 (RAK) 和氨酸-氨酸-氨酸 (RAH) 的温度依赖性构造.
- 探索分子内质子转移在推动形状变化的作用.
- 描述螺旋体 - 球体过渡和螺旋体融化现象.
主要方法:
- 使用温度变化对质子化 (RA15K,RA20K,RA15H) 的气相形状分析.
- 观察400K以下的动力控制结构转换.
- 对螺旋体 - 球体过渡和螺旋体在500 K左右化的分析.
主要成果:
- 观察到动力控制的转变:RA15H的螺旋到球体,RA15K和RA20K的球体到螺旋在400K以下.
- 球体形状膨胀,在更高的温度下变得热带偏好.
- RA15K和RA20K螺旋在500K左右经历广泛的融化过渡,随着体大小的增加而缩小.
- 双质子RA15K在高温下由于残留物排斥而表现出类似子的形状.
结论:
- 内分子质子转移是这些的结构变化的关键驱动因素.
- 温度显著影响质结构,有利于膨胀和热驱动的球体状态.
- 体大小影响螺旋融化的合作性,较大的体显示较窄的过渡.
- 质子流动性很可能参与螺旋形状的融过渡.
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