Department of Biosciences, Biophysical Sciences Institute, Durham University, South Road, Durham, DH1 3LE, UK.
Department of Chemistry, Biophysical Sciences Institute, Durham University, South Road, Durham, DH1 3LE, UK.
Nat Commun. 2022 Sep 8;13(1):5289. doi: 10.1038/s41467-022-32925-6.
Light harvesting is fundamental for production of ATP and reducing equivalents for CO fixation during photosynthesis. However, electronic energy transfer (EET) through a photosystem can harm the photosynthetic apparatus when not balanced with CO. Here, we show that CO binding to the light-harvesting complex modulates EET in photosynthetic cyanobacteria. More specifically, CO binding to the allophycocyanin alpha subunit of the light-harvesting complex regulates EET and its fluorescence quantum yield in the cyanobacterium Synechocystis sp. PCC 6803. CO binding decreases the inter-chromophore distance in the allophycocyanin trimer. The result is enhanced EET in vitro and in live cells. Our work identifies a direct target for CO in the cyanobacterial light-harvesting apparatus and provides insights into photosynthesis regulation.
光能捕获对于光合作用中 ATP 和还原当量的产生至关重要，这些物质是用于 CO2 固定的。然而，当电子能量转移（EET）与 CO 不能达到平衡时，它会对光合作用的装置造成损害。在这里，我们展示了 CO 与捕光复合物的结合可以调节光合蓝藻中的 EET。更具体地说，CO 与捕光复合物中藻蓝蛋白α亚基的结合调节了光合作用蓝藻集胞藻 PCC 6803 的 EET 和其荧光量子产率。CO 结合降低了藻蓝蛋白三聚体中的发色团间距离。其结果是体外和活细胞中 EET 的增强。我们的工作确定了 CO 在蓝藻捕光装置中的直接靶标，并为光合作用的调控提供了新的见解。
