Van Hellemond J J, Simons B, Millenaar F F, Tielens A G
Laboratory of Veterinary Biochemistry, Utrecht University, The Netherlands.
J Eukaryot Microbiol. 1998 Jul-Aug;45(4):426-30. doi: 10.1111/j.1550-7408.1998.tb05094.x.
The constituents of the respiratory chain are believed to differ among the trypanosomatids; bloodstream stages of African trypanosomes and Phytomonas promastigotes oxidize ubiquinol by a ubiquinol:oxygen oxidoreductase, also known as alternative oxidase, whereas Leishmania spp. oxidize ubiquinol via a classic cytochrome-containing respiratory chain. The molecular basis for this elementary difference in ubiquinol oxidation by the mitochondrial electron-transport chain in distinct trypanosomatids was investigated. The presence of a gene encoding the plant-like alternative oxidase could be demonstrated in Phytomonas and Trypanosoma brucei, trypanosomatids that are known to contain alternative oxidase activity. Our results further demonstrated that Leishmania spp. lack a gene encoding the plant-like alternative oxidase, and therefore, all stages of Leishmania spp. will lack the alternative oxidase protein. The observed fundamental differences between the respiratory chains of distinct members of the trypanosomatid family are thus caused by the presence or absence of a gene encoding the plant-like alternative oxidase.
人们认为，锥虫中的呼吸链组成成分有所不同；非洲锥虫的血流阶段以及植滴虫前鞭毛体通过泛醇：氧气氧化还原酶（也称为交替氧化酶）氧化泛醇，而利什曼原虫属则通过经典的含细胞色素呼吸链氧化泛醇。研究了不同锥虫中线粒体电子传递链氧化泛醇这种基本差异的分子基础。在植滴虫和布氏锥虫（已知含有交替氧化酶活性的锥虫）中，可以证明存在编码植物型交替氧化酶的基因。我们的结果进一步表明，利什曼原虫属缺乏编码植物型交替氧化酶的基因，因此，利什曼原虫属的所有阶段都将缺乏交替氧化酶蛋白。因此，在锥虫科不同成员的呼吸链中观察到的基本差异是由编码植物型交替氧化酶的基因的存在或缺失引起的。
