氧光合作用的复杂I型分子NDH的结构
Thomas G Laughlin1,2, Andrew N Bayne3,4, Jean-François Trempe3,4
1Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
Nature
|February 12, 2019
概括
研究人员确定了NAD(P) H脱酶类复合体 (NDH) 的结构,揭示了它如何从铁素接受电子并将其转移到光合作用中至关重要的中. 这一发现阐明了循环电子流的一个关键步骤.
科学领域:
- 光合作用研究
- 膜蛋白复合体的结构生物学
- 电子传输链的生物化学
背景情况:
- 在光合作用中,围绕光系统I (PSI) 的循环电子流对平衡ATP和NADPH至关重要.
- 这一过程中,NAD(P) H脱酶类复合体 (NDH) 是必不可少的,但其结构是未知的.
- NDH与呼吸综合体I共享子单元,但缺乏关键的NAD-PH结合元件,其电子获取机制尚不清楚.
研究的目的:
- 为了阐明NDH复合物的结构.
- 了解从铁素转移到素的电子传递机制.
- 研究氧光合作用特异性 (OPS) 子单位在NDH功能中的作用.
主要方法:
- 使用单粒子冷电子显微镜来确定NDH复合物的结构.
- 这项研究的重点是热性蓝菌Thermosynechococcus elongatus BP-1的NDH复合物.
- 对3.1 Å分辨率结构的分析揭示了子单元和辅助因子的排列.
主要成果:
- 确定了0.42-MDa NDH复合物的3.1 Å结构.
- 揭示了关键的氧光合作用 (OPS) 子单位的排列.
- 在塑结合部位附近发现了一个意想不到的辅助因子和潜在的铁结合部位.
结论:
- 该结构支持OPS子单元在铁中介电子转移中的作用.
- 两个潜在的铁素结合点表明有多种电子转移路径可以有效地减少素.
- 这些发现澄清了光合作用能量平衡的关键组成部分NDH中的电子转移机制.
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