Lateral pH gradient between OXPHOS complex IV and F0F1 ATP-synthase in folded mitochondrial membranes
Lateral pH gradient between OXPHOS complex IV and F0F1 ATP-synthase in folded mitochondrial membranes
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DOI：
10.1038/ncomms4103
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发表时间：
2014-01-01
影响因子：
16.6
通讯作者：
Busch, Karin B.
中科院分区：
文献类型：
--
作者：
Rieger, Bettina;Junge, Wolfgang;Busch, Karin B.
由旋转F0 F1 ATP合成酶驱动的离子驱动的ATP合成为有氧生活提供动力。自从米切尔的开创性的假设，这种合成已经讨论了两个体相之间的质子动力，每一个平衡。在活跃的线粒体中，稳定的质子流在泵和远处的ATP合酶之间循环。在这里，我们确定的横向pH值曲线沿着的p-侧的嵴原位连接成比例的荧光pH敏感的GFP变体OXPHOS复合物IV，质子泵，和二聚体F0 F1 ATP合酶，质子消费者。在呼吸HeLa细胞，我们观察到，在F0 F1二聚体的局部pH值是0.3个单位的酸性比复合物IV。这一发现与从CIV到F0 F1的稳定质子扩散的计算pH曲线一致。观察到的质子动力的横向变化需要对彼得·米切尔的化学渗透提议进行修改。该实验技术可推广到膜微区室中的其他pH依赖性反应。
Ion-driven ATP synthesis by rotary F0F1 ATP-synthase powers aerobic life. Since Mitchell's seminal hypothesis, this synthesis has been discussed in terms of the proton-motive force between two bulk phases, each in equilibrium. In active mitochondria, a steady proton flow cycles between pumps and the distant ATP synthase. Here we determine the lateral pH profile along the p-side of cristae in situ by attaching a ratiometric fluorescent pH-sensitive GFP variant to OXPHOS complex IV, a proton pump, and the dimeric F0F1 ATP-synthase, a proton consumer. In respiring HeLa cells, we observe that the local pH at F0F1 dimers is 0.3 units less acidic than that at complex IV. This finding is consistent with the calculated pH profile for steady proton diffusion from CIV to F0F1. The observed lateral variation in the proton-motive force necessitates a modification to Peter Mitchell's chemiosmotic proposal. The experimental technique can be extended to other pH-dependent reactions in membrane microcompartments.