The heterologous expression of the far-red absorbing chlorophyll (Chl) f in organisms that do not synthesize this pigment has been suggested as a viable solution to expand the solar spectrum that drives oxygenic photosynthesis. In this study, we investigate the functional binding of Chl f to the Photosystem I (PSI) of the cyanobacterium Synechococcus 7002, which has been engineered to express the Chl f synthase gene. By optimizing growth light conditions, one-to-four Chl f pigments were found in the complexes. By using a range of spectroscopic techniques, isolated PSI trimeric complexes were investigated to determine how the insertion of Chl f affects excitation energy transfer and trapping efficiency. The results show that the Chls f are functionally connected to the reaction center of the PSI complex and their presence does not change the overall pigment organization of the complex. Chl f substitutes Chl a (but not the Chl a red forms) while maintaining efficient energy transfer within the PSI complex. At the same time, the introduction of Chl f extends the photosynthetically active radiation of the new hybrid PSI complexes up to 750 nm, which is advantageous in far-red light enriched environments. These conclusions provide insights to engineer the photosynthetic machinery of crops to include Chl f and therefore increase the light-harvesting capability of photosynthesis.

中文翻译：

---

收获远红光：将叶绿素f功能整合到Synechococcus sp。的Photosystem I复合物中。PCC 7002。

已提出在不合成这种色素的生物体中远红外吸收叶绿素（Chl）f的异源表达是扩大驱动氧合光合作用的太阳光谱的可行解决方案。在这项研究中，我们调查Chl f与蓝藻Synechococcus 7002的光系统I（PSI）的功能结合，该蓝藻已被工程化以表达Chl f合酶基因。通过优化生长光条件，在配合物中发现了1-4种Chlf颜料。通过使用一系列的光谱技术，研究了分离的PSI三聚体复合物，以确定Chlf的插入如何影响激发能的转移和俘获效率。结果表明，Chls f在功能上与PSI配合物的反应中心相连，并且它们的存在不会改变配合物的整体色素结构。Chl f替代Chl a（但不是Chl a红色形式），同时在PSI复合物中维持有效的能量转移。同时，Chlf的引入将新的杂化PSI复合物的光合有效辐射扩展到750 nm，这在远红光丰富的环境中是有利的。这些结论为工程化农作物的光合作用机制以包括Chlf提供了见识，从而提高了光合作用的光收集能力。同时，Chlf的引入将新的杂化PSI复合物的光合作用辐射扩展到750 nm，这在远红光丰富的环境中是有利的。这些结论为工程化农作物的光合作用机制以包括Chlf提供了见识，从而提高了光合作用的光收集能力。同时，Chlf的引入将新的杂化PSI复合物的光合作用辐射扩展到750 nm，这在远红光丰富的环境中是有利的。这些结论为工程化农作物的光合作用机制以包括Chlf提供了见识，从而提高了光合作用的光收集能力。