Lehrstuhl für Pflanzenphysiologie, Universität Bayreuth, Universitätsstrasse 30, D-95447 Bayreuth, Germany.
Trends Plant Sci. 2010 Nov;15(11):614-24. doi: 10.1016/j.tplants.2010.07.002.
Photosynthetic organisms require chlorophyll or bacteriochlorophyll for their light trapping and energy transduction activities. The biosynthetic pathways of chlorophyll and bacteriochlorophyll are similar in most of their early steps, except for the reduction of protochlorophyllide (Pchlide) to chlorophyllide. Whereas angiosperms make use of a light-dependent enzyme, cyanobacteria, algae, bryophytes, pteridophytes and gymnosperms contain an additional, light-independent enzyme dubbed dark-operative Pchlide oxidoreductase (DPOR). Anoxygenic photosynthetic bacteria such as Rhodobacter capsulatus and Rhodobacter sphaeroides rely solely on DPOR. Recent atomic resolution of reductase and catalytic components of DPOR from R. sphaeroides and R. capsulatus, respectively, have revealed their similarity to nitrogenase components. In this review, we discuss the two fundamentally different mechanisms of Pchlide reduction in photosynthetic organisms.
光合生物需要叶绿素或细菌叶绿素来进行光捕获和能量转导活动。叶绿素和细菌叶绿素的生物合成途径在其早期的大多数步骤中是相似的，除了原叶绿素（Pchlide）向叶绿素的还原。被子植物利用依赖于光的酶，而蓝细菌、藻类、苔藓植物、蕨类植物和裸子植物则含有另一种非依赖于光的酶，称为暗活性 Pchlide 氧化还原酶（DPOR）。像红杆菌属和球形红杆菌这样的厌氧光合细菌仅依赖 DPOR。最近，对来自球形红杆菌和红杆菌的还原酶和 DPOR 催化成分的原子分辨率解析分别揭示了它们与氮酶成分的相似性。在这篇综述中，我们讨论了光合生物中 Pchlide 还原的两种截然不同的机制。
