Mitochondrial type iron-sulfur cluster assembly in the amitochondriate eukaryotes Trichomonas vaginalis and Giardia intestinalis, as indicated by the phylogeny of IscS.
Mitochondrial type iron-sulfur cluster assembly in the amitochondriate eukaryotes Trichomonas vaginalis and Giardia intestinalis, as indicated by the phylogeny of IscS.
复制标题
IscS 的系统发育表明，线粒体真核生物阴道毛滴虫和肠贾第鞭毛虫中的线粒体型铁硫簇组装。
DOI：
10.1093/oxfordjournals.molbev.a003732
复制
发表时间：
2001
影响因子：
10.7
通讯作者：
Müller,M
中科院分区：
文献类型：
--
作者：
Tachezy,J;Sánchez,LB;Müller,M
磷酸吡哆醛依赖的半胱氨酸脱硫酶（Pyridoxal-5′-phosphate-dependent cysteine脱硫酶，IscS）是细菌和真核生物线粒体中FeS簇组装的关键酶。虽然FeS蛋白对无线粒体厌氧真核生物的能量代谢特别重要，但这些生物中FeS簇形成的信息还没有。我们鉴定并测序了阴道毛滴虫的两个IscS同源物（TvisCS-1和TvisCS-2）和肠贾第鞭毛虫的一个IscS同源物（GiiscS）。TviscS-1、TviscS-2和GiiscS具有涉及半胱氨酸脱硫酶活性的典型保守区域。TviscS-1和TviscS-2的N-末端具有8个氨基酸的延伸，这类似于将蛋白质靶向毛滴虫中的氢化酶体的N-末端前序列。在贾第鞭毛虫的GiiscS中没有明显的前序列，贾第鞭毛虫是一种明显缺乏氢渗透酶或线粒体的生物体。系统发育分析表明，所有真核生物的IscS基因之间的关系密切，包括那些amitochondriates。变形菌的IscS与真核生物的进化枝形成姐妹群，表明在变形菌的线粒体和氢化酶体的内共生祖先中存在与IscS相关的基因。固氮细菌的NifS基因是固氮酶中FeS簇特异性形成所需的IscS同源物，形成了一个更远的组。的FeS簇形成的共同机制，以及在amitochondriate真核生物中的存在下，在naturates的发生表明。此外，这些分析支持毛滴虫氢化酶体和线粒体的共同起源，以及贾第鞭毛虫中线粒体/氢化酶体样细胞器的继发性丢失。
Pyridoxal-5′-phosphate-dependent cysteine desulfurase (IscS) is an essential enzyme in the assembly of FeS clusters in bacteria as well as in the mitochondria of eukaryotes. Although FeS proteins are particularly important for the energy metabolism of amitochondrial anaerobic eukaryotes, there is no information about FeS cluster formation in these organisms. We identified and sequenced two IscS homologs ofTrichomonas vaginalis(TviscS-1 and TviscS-2) and one ofGiardia intestinalis(GiiscS). TviscS-1, TviscS-2, and GiiscS possess the typical conserved regions implicated in cysteine desulfurase activity. N-termini of TviscS-1 and TviscS-2 possess eight amino acid extensions, which resemble the N-terminal presequences that target proteins to hydrogenosomes in trichomonads. No presequence was evident in GiiscS fromGiardia,an organism that apparently lacks hydrogenosmes or mitochondria. Phylogenetic analysis showed a close relationship among all eukaryotic IscS genes including those of amitochondriates. IscS of proteobacteria formed a sister group to the eukaryotic clade, suggesting thatisc-related genes were present in the proteobacterial endosymbiotic ancestor of mitochondria and hydrogenosomes. NifS genes of nitrogen-fixing bacteria, which are IscS homologs required for specific formation of FeS clusters in nitrogenase, formed a more distant group. The phylogeny indicates the presence of a common mechanism for FeS cluster formation in mitochondriates as well as in amitochondriate eukaryotes. Furthermore, the analyses support a common origin ofTrichomonashydrogenosomes and mitochondria, as well as secondary loss of mitochondrion/hydrogenosome-like organelles inGiardia.