在二甲状腺毒素转位域中,丁蛋白质质子和 conformational 切换
Mykola V Rodnin1, Victor Vasques-Montes1, Alexander Kyrychenko1,2
1Department of Biochemistry and Molecular Biology, University of Kansas School of Medicine, Kansas City, KS 66160, USA.
Toxins
|July 28, 2023
概括
在白病毒素中的histidine残留物的质子化.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 结构生物学 结构生物学
背景情况:
- 甲状腺毒素转位 (T-) 域促进细胞进入催化域.
- 酸介导的T域的作用与histidine残留的质子化有关.
研究的目的:
- 为了研究喉毒素T-domain中的初始形状变化.
- 为了确定在T-域中的histidine残留的pKa值.
- 评估特定的希斯蒂丁残留物在酸诱导的形状变化中的作用.
主要方法:
- 恒定pH分子动力学模拟
- 通过NMR监测的pH标化值.
- 圆形二重化谱光学 圆形二重化谱光学
- 光光谱学是一种光谱学.
- 在X射线晶体学.
主要成果:
- 实验和计算方法描述了野生类型和H223Q/H257Q突变T域.
- 核磁共振定位显示了histidine pKa值在6.2至6.8之间,有两个未指定的峰值.
- 模拟显示胺pKa值在3.0到6.5之间,H251和H257是最少的质子化.
- H223Q/H257Q突变使蛋白质结构稳定在pH值5.5,减少了膜破坏.
结论:
- 该研究报告了T-域歇斯蒂丁残留物的第一个实验pKa值.
- 希斯蒂丁残留物H223和H257的质子化对于酸诱导的形状变化至关重要.
- 在T域中,所有六个histidines的合作质子发生不了.
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