Institute of Parasitology, Biology Centre, Academy of Sciences of the Czech Republic, and Faculty of Science, University of South Bohemia, Czech Republic.
Plant Cell. 2011 Sep;23(9):3454-62. doi: 10.1105/tpc.111.089102. Epub 2011 Sep 30.
Most photosynthetic eukaryotes synthesize both heme and chlorophyll via a common tetrapyrrole biosynthetic pathway starting from glutamate. This pathway was derived mainly from cyanobacterial predecessor of the plastid and differs from the heme synthesis of the plastid-lacking eukaryotes. Here, we show that the coral-associated alveolate Chromera velia, the closest known photosynthetic relative to Apicomplexa, possesses a tetrapyrrole pathway that is homologous to the unusual pathway of apicomplexan parasites. We also demonstrate that, unlike other eukaryotic phototrophs, Chromera synthesizes chlorophyll from glycine and succinyl-CoA rather than glutamate. Our data shed light on the evolution of the heme biosynthesis in parasitic Apicomplexa and photosynthesis-related biochemical processes in their ancestors.
大多数光合真核生物通过从谷氨酸开始的共同四吡咯生物合成途径合成血红素和叶绿素。该途径主要来源于质体的蓝细菌前体，与缺乏质体的真核生物的血红素合成途径不同。在这里，我们表明，与 Apicomplexa 最接近的珊瑚相关的内共生体 Chromera velia 具有与 Apicomplexa 寄生虫不寻常途径同源的四吡咯途径。我们还证明，与其他真核光合生物不同，Chromera 不是从谷氨酸合成叶绿素，而是从甘氨酸和琥珀酰辅酶 A 合成。我们的数据阐明了寄生 Apicomplexa 中血红素生物合成的进化以及它们祖先中与光合作用相关的生化过程。
