对 caa3 型细胞染色体氧化酶中电子转移的结构性见解
Joseph A Lyons1, David Aragão, Orla Slattery
1Department of Chemical and Environmental Sciences, University of Limerick, Limerick, Ireland.
Nature
|July 6, 2012
概括
在Thermus thermophilus的晶体结构中,可以发现一个融合的cytochrome c域,这表明电子进入和退出位置不同. 这挑战了先前的电子转移在海姆铜氧化酶中的模型.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 微生物学 微生物学
背景情况:
- 细胞染色体c氧化酶 (HCO) 酶对于细胞呼吸至关重要,催化氧气减少和质子.
- 从细胞染色体c向氧化酶的电子转移是必不可少的,通常涉及过渡性蛋白质协会.
- 目前的模型建议电子进入和退出在细胞染色体c的相同位置.
研究的目的:
- 为了确定来自Thermus thermophilus的caa3型细胞染色体氧化酶的晶体结构.
- 阐明这种酶中电子转移的机制,特别是与合的细胞染色体c域.
- 识别与酶复合体相关的新型子单元和脂质.
主要方法:
- 在双连续的中位相中,Thermus thermophilus 细胞染色体c氧化酶的结晶,使用合成单糖醇.
- 在2.36 Å分辨率的X射线晶体学.
- 分析电子密度图,以确定结构部件及其排列.
主要成果:
- 晶体结构揭示了一种新型的整体膜子单元和嵌入的本地糖甘油脂.
- 这种酶具有共价连接的细胞染色体c域 (cupredoxin/cytochrome c).
- 该结构表明电子进入和退出细胞染色体c上的不同位置,与可溶性细胞染色体c机制不同.
结论:
- 与可溶性细胞染色体c相比,化细胞染色体c域架构需要替代的电子转移途径.
- 这些发现表明,在这种铜氧化酶中,与经典的质子门机制有所不同.
- 这项研究为呼吸酶中电子转移的结构基础提供了新的见解.
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