Nitrogenase-like Biosynthesis of (Bacterio)chlorophylls

光合作用对全球能源需求的捕获在很大程度上取决于（细菌）叶绿素的生物合成。此外，将大气中的二氮还原为氨对生态系统的补充至关重要。氮酶复杂的生物化学过程对叶绿素和细菌叶绿素的形成起着至关重要的作用。叶绿素和细菌叶绿素的生物合成都需要对原叶绿素D环的C17-C18双键进行立体特异性还原，这种还原可以由类似于氮酶的暗操作原叶绿素氧化还原酶（dark-operative protoophylllide oxidoreductase， DPOR）催化。所有bchl的生物合成都需要一种称为叶绿素氧化还原酶（COR）的第二种氮酶样酶来对叶绿素的C7-C8位进行立体特异性还原。在这里，我们想要阐明COR、DPOR和氮酶之间的催化差异。我们打算解析底物结合的COR配合物的三维结构。此外，我们还打算鉴定COR的人工小分子底物光谱，这些结果将有助于进一步了解最近发现的促进小碳氢化合物形成的氮酶对CO的还原能力。

The photosynthetic capture of the global energy demand vitally depends on the biosynthesis of (bacterio)chlorophylls. Also the reduction of atmospheric dinitrogen to ammonia is essential for the fuelling of ecosystems. The sophisticated biochemistry of nitrogenase plays a fundamental role for the formation of chlorophylls and bacteriochlorophylls. The biosynthesis of both, chlorophylls and bacteriochlorophylls requires the stereospecific reduction of the C17-C18 double bond of ring D of protochlorophyllide which can be catalyzed by the nitrogenase-like enzyme dark-operative protochlorophyllide oxidoreductase (DPOR). The biosynthesis of all Bchls requires a second nitrogenase-like enzyme termed chlorophyllide oxidoreductase (COR) for the stereospecific reduction of the C7-C8 position of chlorophyllide. Here we want to elucidate the catalytic differences between COR, DPOR and nitrogenase. We intend to resolve the three-dimensional structure of the substrate-bound COR complex. Furthermore, we intend to identify the artificial small molecule substrate spectrum of COR. These results will help to further understand the recently discovered CO reducing capacity of nitrogenase which facilitates the formation of small hydrocarbons.