An anaerobic mitochondrion that produces hydrogen
An anaerobic mitochondrion that produces hydrogen
复制标题
DOI：
10.1038/nature03343
复制
发表时间：
2005-03-03
期刊：
影响因子：
64.8
通讯作者：
Hackstein, JHP
中科院分区：
文献类型：
--
作者：
Boxma, B;de Graaf, RM;Hackstein, JHP
氢基因体是产生 ATP 和氢气的细胞器 (1)，存在于各种不相关的真核生物中，例如厌氧鞭毛虫、壶菌真菌和纤毛虫 (2)。尽管所有这些细胞器都会产生氢气，但这些生物体的氢酶体在结构和代谢上都截然不同，就像线粒体一样，也存在很大差异(3)。这些差异导致了关于氢酶体进化起源的持续争论(4,5)。在这里，我们表明，在蟑螂后肠中繁衍生息的厌氧纤毛虫卵圆夜蛾的氢酶体保留了编码线粒体电子传递链成分的基本基因组。系统发育分析表明，这些蛋白质与其来自需氧纤毛虫的同源物聚集在一起。此外，还鉴定了线粒体蛋白质组的几种核编码成分，例如丙酮酸脱氢酶和复合物 II。 N. ovalis 氢酶体对线粒体复合物 I 的抑制剂敏感，并产生琥珀酸作为主要代谢终产物 - 厌氧线粒体的典型生化特征 (3)。氢气的产生，加上编码呼吸链成分的基因组的存在，以及厌氧线粒体的生化特征，将卵圆神经细胞器确定为线粒体和氢酶体之间缺失的一环。
Hydrogenosomes are organelles that produce ATP and hydrogen(1), and are found in various unrelated eukaryotes, such as anaerobic flagellates, chytridiomycete fungi and ciliates(2). Although all of these organelles generate hydrogen, the hydrogenosomes from these organisms are structurally and metabolically quite different, just like mitochondria where large differences also exist(3). These differences have led to a continuing debate about the evolutionary origin of hydrogenosomes(4,5). Here we show that the hydrogenosomes of the anaerobic ciliate Nyctotherus ovalis, which thrives in the hindgut of cockroaches, have retained a rudimentary genome encoding components of a mitochondrial electron transport chain. Phylogenetic analyses reveal that those proteins cluster with their homologues from aerobic ciliates. In addition, several nucleus-encoded components of the mitochondrial proteome, such as pyruvate dehydrogenase and complex II, were identified. The N. ovalis hydrogenosome is sensitive to inhibitors of mitochondrial complex I and produces succinate as a major metabolic end product - biochemical traits typical of anaerobic mitochondria(3). The production of hydrogen, together with the presence of a genome encoding respiratory chain components, and biochemical features characteristic of anaerobic mitochondria, identify the N. ovalis organelle as a missing link between mitochondria and hydrogenosomes.