Molecular Analysis of the Hydrogenosomal Ferredoxin of the Anaerobic Protist Trichomonas vaginalis

• Published in: Proceedings of the National Academy of Sciences - PNAS 1990-08, Vol.87 (16), p.6097-6101
• Main Authors: Johnson, Patricia J., D'Oliveira, Christine E., Gorrell, Thomas E., Muller, Miklos
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino acids; Anaerobiosis; Analytical, structural and metabolic biochemistry; Animals; Base Sequence; Biological and medical sciences; Blotting, Southern; DNA; DNA - genetics; DNA - isolation & purification; Ferredoxins; Ferredoxins - genetics; Ferredoxins - metabolism; Fundamental and applied biological sciences. Psychology; Gene Library; Genes; Messenger RNA; Metalloproteins; Mitochondria; Molecular Sequence Data; Nucleotides; Organelles; Other metalloproteins; Protein Conformation; Proteins; Restriction Mapping; RNA; RNA - genetics; RNA - isolation & purification; Sequence Homology, Nucleic Acid; Sequencing; Trichomonas vaginalis; Trichomonas vaginalis - genetics; Trichomonas vaginalis - metabolism
• ISSN: 0027-8424; 1091-6490
• 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 > 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.