Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany.
J Exp Bot. 2015 May;66(9):2373-400. doi: 10.1093/jxb/eru495. Epub 2014 Dec 24.
During plant development and in response to fluctuating environmental conditions, large changes in leaf assimilation capacity and in the metabolic consumption of ATP and NADPH produced by the photosynthetic apparatus can occur. To minimize cytotoxic side reactions, such as the production of reactive oxygen species, photosynthetic electron transport needs to be adjusted to the metabolic demand. The cytochrome b6f complex and chloroplast ATP synthase form the predominant sites of photosynthetic flux control. Accordingly, both respond strongly to changing environmental conditions and metabolic states. Usually, their contents are strictly co-regulated. Thereby, the capacity for proton influx into the lumen, which is controlled by electron flux through the cytochrome b6f complex, is balanced with proton efflux through ATP synthase, which drives ATP synthesis. We discuss the environmental, systemic, and metabolic signals triggering the stoichiometry adjustments of ATP synthase and the cytochrome b6f complex. The contribution of transcriptional and post-transcriptional regulation of subunit synthesis, and the importance of auxiliary proteins required for complex assembly in achieving the stoichiometry adjustments is described. Finally, current knowledge on the stability and turnover of both complexes is summarized.
在植物的生长发育过程中，以及应对环境变化时，叶片的同化能力以及光合作用装置产生的 ATP 和 NADPH 的代谢消耗会发生巨大变化。为了将细胞毒性副反应（如活性氧的产生）最小化，光合电子传递需要根据代谢需求进行调整。细胞色素 b6f 复合物和叶绿体 ATP 合酶是光合作用通量控制的主要部位。因此，它们都对环境变化和代谢状态有强烈的响应。通常，它们的含量是严格共同调节的。通过细胞色素 b6f 复合物的电子流控制质子流入腔的能力，与通过 ATP 合酶驱动 ATP 合成的质子外排相平衡。我们讨论了触发 ATP 合酶和细胞色素 b6f 复合物化学计量调节的环境、系统和代谢信号。描述了亚基合成的转录和转录后调节的贡献，以及在实现化学计量调节中组装辅助蛋白的重要性。最后，总结了关于这两个复合物的稳定性和周转率的现有知识。
