大型无水聚氨酸离子:证据表明延伸螺旋和更紧状态的出现
1Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA.
Journal of the American Chemical Society
|July 18, 2001
概括
大型聚氨酸采用明显的延长或紧的结构. 紧的,折叠的螺旋线圈状态在较长的上占主导地位,由电荷和驱动.
科学领域:
- 生物物理化学 生物物理化学
- 计算化学计算化学
- 结构生物学 结构生物学
背景情况:
- 具有多重电荷的,如聚氨酸,表现出复杂的结构性行为.
- 了解折叠对于破译蛋白质结构-功能关系至关重要.
研究的目的:
- 为了研究大型多重电荷聚氨酸的构造格局.
- 用实验和计算方法区分扩展和紧的结构状态.
主要方法:
- 对具有不同链长度 (n) 的聚氨酸进行了离子流动性测量.
- 用分子建模计算来分析形状.
- 来自实验的碰撞截面数据与计算预测进行了比较.
主要成果:
- 观察到两种不同的形状序列:延长型和紧型.
- 长长的形状,以延伸的螺旋结构为特征,在n = 18-39时普遍存在.
- 紧的形状,被确定为一种新的折叠螺旋线圈状态,在n > 32时成为主导.
结论:
- 聚氨酸可以存在至少两个稳定的构造状态.
- 折叠螺旋线圈状态代表了一个具有可比的螺旋和线圈尺寸的新型调节器类型.
- 电荷稳定和之间的平衡决定了扩展状态和紧状态之间的竞争.
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