Lassen Lærke Münter, Nielsen Agnieszka Zygadlo, Ziersen Bibi, Gnanasekaran Thiyagarajan, Møller Birger Lindberg, Jensen Poul Erik
UNIK Center for Synthetic Biology, Interdisciplinary Research Center "bioSYNergy", the VILLUM Research Center "Plant Plasticity", Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen , Thorvaldsensvej 40, DK-1871 Frederiksberg C, Copenhagen, Denmark.
ACS Synth Biol. 2014 Jan 17;3(1):1-12. doi: 10.1021/sb400136f. Epub 2013 Dec 23.
Photosynthesis in plants, green algae, and cyanobacteria converts solar energy into chemical energy in the form of ATP and NADPH, both of which are used in primary metabolism. However, often more reducing power is generated by the photosystems than what is needed for primary metabolism. In this review, we discuss the development in the research field, focusing on how the photosystems can be used as synthetic biology building blocks to channel excess reducing power into light-driven production of alternative products. Plants synthesize a large number of high-value bioactive natural compounds. Some of the key enzymes catalyzing their biosynthesis are the cytochrome P450s situated in the endoplasmic reticulum. However, bioactive compounds are often synthesized in low quantities in the plants and are difficult to produce by chemical synthesis due to their often complex structures. Through a synthetic biology approach, enzymes with a requirement for reducing equivalents as cofactors, such as the cytochrome P450s, can be coupled directly to the photosynthetic energy output to obtain environmentally friendly production of complex chemical compounds. By relocating cytochrome P450s to the chloroplasts, reducing power can be diverted toward the reactions catalyzed by the cytochrome P450s. This provides a sustainable production method for high-value compounds that potentially can solve the problem of NADPH regeneration, which currently limits the biotechnological uses of cytochrome P450s. We describe the approaches that have been taken to couple enzymes to photosynthesis in vivo and to photosystem I in vitro and the challenges associated with this approach to develop new green production platforms.
植物、绿藻和蓝细菌中的光合作用将太阳能转化为ATP和NADPH形式的化学能，这两者都用于初级代谢。然而，光系统产生的还原力往往超过初级代谢所需。在这篇综述中，我们讨论了该研究领域的进展，重点关注如何将光系统用作合成生物学的构建模块，将多余的还原力引导到光驱动的替代产品生产中。植物合成大量高价值的生物活性天然化合物。催化其生物合成的一些关键酶是位于内质网中的细胞色素P450。然而，生物活性化合物在植物中的合成量通常较低，并且由于其结构往往复杂，难以通过化学合成生产。通过合成生物学方法，需要还原当量作为辅因子的酶，如细胞色素P450，可以直接与光合能量输出耦合，以实现复杂化合物的环境友好型生产。通过将细胞色素P450重新定位到叶绿体中，还原力可以转向由细胞色素P450催化的反应。这为高价值化合物提供了一种可持续的生产方法，有可能解决NADPH再生的问题，目前NADPH再生限制了细胞色素P450的生物技术应用。我们描述了在体内将酶与光合作用耦合以及在体外将酶与光系统I耦合所采用的方法，以及与开发新的绿色生产平台的这种方法相关的挑战。
