核细胞V-ATPase的嵌入膜的VO电机的原子模型
Mohammad T Mazhab-Jafari1, Alexis Rohou2, Carla Schmidt3
1Molecular Structure and Function Program, The Hospital for Sick Children, Toronto, Ontario M5G 0A4, Canada.
Nature
|November 4, 2016
概括
真空型ATPases (V-ATPases) 是重要的质子. 研究人员绘制了V-ATPase
科学领域:
- 生物化学
- 结构生物学
- 分子生物学
背景情况:
- 真空型ATPases (V-ATPases) 是重要的ATP驱动的质子.
- 它们调节重要的细胞过程,包括内细胞分裂,溶酶体降解和离子运输.
- 之前对V-ATPases的结构研究受到酶变异性的限制,阻碍了原子模型的构建.
研究的目的:
- 确定V-ATPase的膜结合VO复合物的高分辨率结构.
- 通过V-ATPase电机阐明质子转移的机制.
- 在V-ATPase复合体内识别新型子单元.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 来获得VO复合物的3.9-Å分辨率图.
- 在*Saccharomyces cerevisiae*中通过营养饥饿诱导V-ATPase解离和自身抑制.
- 构建了VO子单位的原子模型,包括一个新发现的"f"子单位.
主要成果:
- 揭示了VO子单位ac8c'c′′de和新型子单位f的原子结构.
- 通过a子单元和c环之间的空腔形成的质子运输半通道.
- 在c环中表现出携带质子的谷氨酸残留物不对称的分布,以及它们与子单元a的相互作用.
结论:
- 确定的VO结构为V-ATPases的旋转机制提供了前所未有的洞察力.
- 这些发现表明了一种连续的质子化/解质子化机制与ATP水解驱动的旋转相结合.
- 这项研究提升了我们对生物旋转电机中的质子转移的理解.
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