Johnson P J, d'Oliveira C E, Gorrell T E, Müller M
Department of Microbiology and Immunology, University of California School of Medicine, Los Angeles 90024.
Proc Natl Acad Sci U S A. 1990 Aug;87(16):6097-101. doi: 10.1073/pnas.87.16.6097.
We have determined the primary structure of the [2Fe-2S]ferredoxin of the anaerobic protist Trichomonas vaginalis. This protein, situated in the hydrogenosome, is composed of 93 amino acids. A comparison of T. vaginalis ferredoxin with greater than 80 other ferredoxins shows the closest similarity to [2Fe-2S]putidaredoxin of the aerobic bacterium Pseudomonas putida and a lesser one to mitochondrial [2Fe-2S]ferredoxins of vertebrates. This similarity is reflected in the overall primary structure and in the spacing of cysteine residues coordinating the iron-sulfur center. The primary structure, but not the environment of the iron-sulfur center, also shows similarity with [2Fe-2S]ferredoxins of photosynthetic organisms and halobacteria. We have cloned and analyzed the T. vaginalis ferredoxin gene. The gene is present in a single copy and devoid of introns. It gives rise to a transcript with unusually short 5' and 3' untranslated regions of 16 and 18 nucleotides, respectively. DNA sequence analysis of the gene predicts an additional 8 amino acids at the amino terminus which are absent from the purified protein. This amino-terminal region of the protein is characterized by properties typical of mitochondrial presequences.
我们已经确定了厌氧原生生物阴道毛滴虫的[2Fe-2S]铁氧化还原蛋白的一级结构。这种位于氢化酶体中的蛋白质由93个氨基酸组成。将阴道毛滴虫铁氧化还原蛋白与80多种其他铁氧化还原蛋白进行比较，发现它与需氧细菌恶臭假单胞菌的[2Fe-2S]恶臭铁氧化还原蛋白最为相似，而与脊椎动物线粒体的[2Fe-2S]铁氧化还原蛋白的相似性稍低。这种相似性体现在整体一级结构以及配位铁硫中心的半胱氨酸残基的间距上。一级结构，而非铁硫中心的环境，也显示出与光合生物和嗜盐菌的[2Fe-2S]铁氧化还原蛋白相似。我们已经克隆并分析了阴道毛滴虫铁氧化还原蛋白基因。该基因以单拷贝形式存在且无内含子。它产生的转录本具有异常短的5'和3'非翻译区，分别为16个和18个核苷酸。对该基因的DNA序列分析预测，在氨基末端还有8个氨基酸，而纯化后的蛋白质中没有这些氨基酸。该蛋白质的这个氨基末端区域具有线粒体前序列的典型特征。
