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Tachezy J, Makki A, Hrdý I. The hydrogenosomes of Trichomonas vaginalis. J Eukaryot Microbiol 2022; 69:e12922. [PMID: 35567536 DOI: 10.1111/jeu.12922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This review is dedicated to the 50th anniversary of the discovery of hydrogenosomes by Miklós Müller and Donald Lindmark, which we will celebrate the following year. It was a long journey from the first observation of enigmatic rows of granules in trichomonads at the end of the 19th century to their first biochemical characterization in 1973. The key experiments by Müller and Lindmark revealed that the isolated granules contain hydrogen-producing hydrogenase, similar to some anaerobic bacteria-a discovery that gave birth to the field of hydrogenosomes. It is also important to acknowledge the parallel work of the team of Apolena Čerkasovová, Jiří Čerkasov, and Jaroslav Kulda, who demonstrated that these granules, similar to mitochondria, produce ATP. However, the evolutionary origin of hydrogenosomes remained enigmatic until the turn of the millennium, when it was finally accepted that hydrogenosomes and mitochondria evolved from a common ancestor. After a historical introduction, the review provides an overview of hydrogenosome biogenesis, hydrogenosomal protein import, and the relationship between the peculiar structure of membrane translocases and its low inner membrane potential due to the lack of respiratory complexes. Next, it summarizes the current state of knowledge on energy metabolism, the oxygen defense system, and iron/sulfur cluster assembly.
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Affiliation(s)
- Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25242 Vestec, Czech Republic
| | - Abhijith Makki
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25242 Vestec, Czech Republic
| | - Ivan Hrdý
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25242 Vestec, Czech Republic
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2
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Lewis WH, Lind AE, Sendra KM, Onsbring H, Williams TA, Esteban GF, Hirt RP, Ettema TJG, Embley TM. Convergent Evolution of Hydrogenosomes from Mitochondria by Gene Transfer and Loss. Mol Biol Evol 2020; 37:524-539. [PMID: 31647561 PMCID: PMC6993867 DOI: 10.1093/molbev/msz239] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Hydrogenosomes are H2-producing mitochondrial homologs found in some anaerobic microbial eukaryotes that provide a rare intracellular niche for H2-utilizing endosymbiotic archaea. Among ciliates, anaerobic and aerobic lineages are interspersed, demonstrating that the switch to an anaerobic lifestyle with hydrogenosomes has occurred repeatedly and independently. To investigate the molecular details of this transition, we generated genomic and transcriptomic data sets from anaerobic ciliates representing three distinct lineages. Our data demonstrate that hydrogenosomes have evolved from ancestral mitochondria in each case and reveal different degrees of independent mitochondrial genome and proteome reductive evolution, including the first example of complete mitochondrial genome loss in ciliates. Intriguingly, the FeFe-hydrogenase used for generating H2 has a unique domain structure among eukaryotes and appears to have been present, potentially through a single lateral gene transfer from an unknown donor, in the common aerobic ancestor of all three lineages. The early acquisition and retention of FeFe-hydrogenase helps to explain the facility whereby mitochondrial function can be so radically modified within this diverse and ecologically important group of microbial eukaryotes.
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Affiliation(s)
- William H Lewis
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle-Upon-Tyne, United Kingdom.,Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.,Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Wageningen, The Netherlands
| | - Anders E Lind
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Kacper M Sendra
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle-Upon-Tyne, United Kingdom
| | - Henning Onsbring
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.,Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Wageningen, The Netherlands
| | - Tom A Williams
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Genoveva F Esteban
- Department of Life and Environmental Sciences, Bournemouth University, Poole, United Kingdom
| | - Robert P Hirt
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle-Upon-Tyne, United Kingdom
| | - Thijs J G Ettema
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.,Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Wageningen, The Netherlands
| | - T Martin Embley
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle-Upon-Tyne, United Kingdom
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3
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Garg S, Stölting J, Zimorski V, Rada P, Tachezy J, Martin WF, Gould SB. Conservation of Transit Peptide-Independent Protein Import into the Mitochondrial and Hydrogenosomal Matrix. Genome Biol Evol 2015; 7:2716-26. [PMID: 26338186 PMCID: PMC4607531 DOI: 10.1093/gbe/evv175] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The origin of protein import was a key step in the endosymbiotic acquisition of mitochondria. Though the main translocon of the mitochondrial outer membrane, TOM40, is ubiquitous among organelles of mitochondrial ancestry, the transit peptides, or N-terminal targeting sequences (NTSs), recognised by the TOM complex, are not. To better understand the nature of evolutionary conservation in mitochondrial protein import, we investigated the targeting behavior of Trichomonas vaginalis hydrogenosomal proteins in Saccharomyces cerevisiae and vice versa. Hydrogenosomes import yeast mitochondrial proteins even in the absence of their native NTSs, but do not import yeast cytosolic proteins. Conversely, yeast mitochondria import hydrogenosomal proteins with and without their short NTSs. Conservation of an NTS-independent mitochondrial import route from excavates to opisthokonts indicates its presence in the eukaryote common ancestor. Mitochondrial protein import is known to entail electrophoresis of positively charged NTSs across the electrochemical gradient of the inner mitochondrial membrane. Our present findings indicate that mitochondrial transit peptides, which readily arise from random sequences, were initially selected as a signal for charge-dependent protein targeting specifically to the mitochondrial matrix. Evolutionary loss of the electron transport chain in hydrogenosomes and mitosomes lifted the selective constraints that maintain positive charge in NTSs, allowing first the NTS charge, and subsequently the NTS itself, to be lost. This resulted in NTS-independent matrix targeting, which is conserved across the evolutionary divide separating trichomonads and yeast, and which we propose is the ancestral state of mitochondrial protein import.
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Affiliation(s)
- Sriram Garg
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Jan Stölting
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Verena Zimorski
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Petr Rada
- Department of Parasitology, Charles University in Prague, Faculty of Science, Czech Republic
| | - Jan Tachezy
- Department of Parasitology, Charles University in Prague, Faculty of Science, Czech Republic
| | - William F Martin
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sven B Gould
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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4
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Brás XP, Zimorski V, Bolte K, Maier UG, Martin WF, Gould SB. Knockout of the abundant Trichomonas vaginalis
hydrogenosomal membrane protein Tv
HMP23 increases hydrogenosome size but induces no compensatory up-regulation of paralogous copies. FEBS Lett 2013; 587:1333-9. [DOI: 10.1016/j.febslet.2013.03.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 02/28/2013] [Accepted: 03/01/2013] [Indexed: 11/25/2022]
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5
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Zimorski V, Major P, Hoffmann K, Brás XP, Martin WF, Gould SB. The N-terminal sequences of four major hydrogenosomal proteins are not essential for import into hydrogenosomes of Trichomonas vaginalis. J Eukaryot Microbiol 2012; 60:89-97. [PMID: 23210891 DOI: 10.1111/jeu.12012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 09/18/2012] [Accepted: 09/18/2012] [Indexed: 11/26/2022]
Abstract
The human pathogen Trichomonas vaginalis harbors hydrogenosomes, organelles of mitochondrial origin that generate ATP through hydrogen-producing fermentations. They contain neither genome nor translation machinery, but approximately 500 proteins that are imported from the cytosol. In contrast to well-studied organelles like Saccharomyces mitochondria, very little is known about how proteins are transported across the two membranes enclosing the hydrogenosomal matrix. Recent studies indicate that-in addition to N-terminal transit peptides-internal targeting signals might be more common in hydrogenosomes than in mitochondria. To further characterize the extent to which N-terminal and internal motifs mediate hydrogenosomal protein targeting, we transfected Trichomonas with 24 hemagglutinin (HA) tag fusion constructs, encompassing 13 different hydrogenosomal and cytosolic proteins of the parasite. Hydrogenosomal targeting of these proteins was analyzed by subcellular fractionation and independently by immunofluorescent localization. The investigated proteins include some of the most abundant hydrogenosomal proteins, such as pyruvate ferredoxin oxidoreductase (PFO), which possesses an amino-terminal targeting signal that is processed on import into hydrogenosomes, but is shown here not to be required for import into hydrogenosomes. Our results demonstrate that the deletion of N-terminal signals of hydrogenosomal precursors generally has little, if any, influence upon import into hydrogenosomes. Although the necessary and sufficient signals for hydrogenosomal import recognition appear complex, targeting to the organelle is still highly specific, as demonstrated by the finding that six HA-tagged glycolytic enzymes, highly expressed under the same promoter as other constructs studied here, localized exclusively to the cytosol and did not associate with hydrogenosomes.
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Affiliation(s)
- Verena Zimorski
- Institute for Molecular Evolution, Heinrich-Heine-University Duesseldorf, D-40225, Duesseldorf, Germany
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Müller M, Mentel M, van Hellemond JJ, Henze K, Woehle C, Gould SB, Yu RY, van der Giezen M, Tielens AGM, Martin WF. Biochemistry and evolution of anaerobic energy metabolism in eukaryotes. Microbiol Mol Biol Rev 2012; 76:444-95. [PMID: 22688819 PMCID: PMC3372258 DOI: 10.1128/mmbr.05024-11] [Citation(s) in RCA: 505] [Impact Index Per Article: 42.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Major insights into the phylogenetic distribution, biochemistry, and evolutionary significance of organelles involved in ATP synthesis (energy metabolism) in eukaryotes that thrive in anaerobic environments for all or part of their life cycles have accrued in recent years. All known eukaryotic groups possess an organelle of mitochondrial origin, mapping the origin of mitochondria to the eukaryotic common ancestor, and genome sequence data are rapidly accumulating for eukaryotes that possess anaerobic mitochondria, hydrogenosomes, or mitosomes. Here we review the available biochemical data on the enzymes and pathways that eukaryotes use in anaerobic energy metabolism and summarize the metabolic end products that they generate in their anaerobic habitats, focusing on the biochemical roles that their mitochondria play in anaerobic ATP synthesis. We present metabolic maps of compartmentalized energy metabolism for 16 well-studied species. There are currently no enzymes of core anaerobic energy metabolism that are specific to any of the six eukaryotic supergroup lineages; genes present in one supergroup are also found in at least one other supergroup. The gene distribution across lineages thus reflects the presence of anaerobic energy metabolism in the eukaryote common ancestor and differential loss during the specialization of some lineages to oxic niches, just as oxphos capabilities have been differentially lost in specialization to anoxic niches and the parasitic life-style. Some facultative anaerobes have retained both aerobic and anaerobic pathways. Diversified eukaryotic lineages have retained the same enzymes of anaerobic ATP synthesis, in line with geochemical data indicating low environmental oxygen levels while eukaryotes arose and diversified.
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Affiliation(s)
| | - Marek Mentel
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Jaap J. van Hellemond
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Katrin Henze
- Institute of Molecular Evolution, University of Düsseldorf, Düsseldorf, Germany
| | - Christian Woehle
- Institute of Molecular Evolution, University of Düsseldorf, Düsseldorf, Germany
| | - Sven B. Gould
- Institute of Molecular Evolution, University of Düsseldorf, Düsseldorf, Germany
| | - Re-Young Yu
- Institute of Molecular Evolution, University of Düsseldorf, Düsseldorf, Germany
| | - Mark van der Giezen
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Aloysius G. M. Tielens
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, Netherlands
| | - William F. Martin
- Institute of Molecular Evolution, University of Düsseldorf, Düsseldorf, Germany
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7
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Lantsman Y, Tan KSW, Morada M, Yarlett N. Biochemical characterization of a mitochondrial-like organelle from Blastocystis sp. subtype 7. MICROBIOLOGY-SGM 2008; 154:2757-2766. [PMID: 18757809 DOI: 10.1099/mic.0.2008/017897-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A mitochondrion-like organelle (MLO) was isolated from isotonic homogenates of Blastocystis. The organelle sedimented at 5000 g for 10 min, and had an isopycnic density in sucrose of 1.2 g ml(-1). Biochemical characterization enabled the demonstration of several key enzymes that allowed the construction of a metabolic pathway consisting of an incomplete Krebs cycle linked to the oxygen-sensitive enzymes pyruvate : NADP(+) oxidoreductase (PNO), acetate : succinate CoA transferase (ASCT) and succinate thiokinase (STK), which cumulatively are responsible for recycling CoA and generating ATP. The organelle differs from typical aerobic mitochondria in possessing an oxygen-sensitive PNO that can use FAD(+) or FMN(+) as electron acceptor but is inactive with NAD(+), Spinacia oleracea ferredoxin or Clostridium pasteurianum ferredoxin. A gene with 77 % sequence similarity to the PNO mitochondrion precursor cluster from Euglena gracilis sp[Q941N5] was identified in the Blastocystis genome database. A second cluster with 56 % sequence similarity to the pyruvate : ferredoxin oxidoreductase (PFOR) from Trichomonas vaginalis was also identified, which is in agreement with the concept that the PNO gene arose through the fusion of a eubacterial gene for PFOR with the gene for NADPH : cytochrome p450 reductase. Hydrogenase activity was not detected under the conditions used in this study. The Blastocystis oranelle therefore demonstrates significant biochemical differences from traditional mitochondria and hydrogenosomes, but possesses features of both. Based upon the results of this study, the Blastocystis organelle falls into the category of a MLO.
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Affiliation(s)
- Yelena Lantsman
- Haskins Laboratories, Pace University, New York, NY 10038, USA
| | - Kevin S W Tan
- Laboratory of Molecular and Cellular Parasitology and Infectious Disease Programme, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore
| | - Mary Morada
- Haskins Laboratories, Pace University, New York, NY 10038, USA
| | - Nigel Yarlett
- Department of Chemistry and Physical Sciences, Pace University, New York, NY 10038, USA.,Haskins Laboratories, Pace University, New York, NY 10038, USA
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Ali V, Nozaki T. Current therapeutics, their problems, and sulfur-containing-amino-acid metabolism as a novel target against infections by "amitochondriate" protozoan parasites. Clin Microbiol Rev 2007; 20:164-87. [PMID: 17223627 PMCID: PMC1797636 DOI: 10.1128/cmr.00019-06] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The "amitochondriate" protozoan parasites of humans Entamoeba histolytica, Giardia intestinalis, and Trichomonas vaginalis share many biochemical features, e.g., energy and amino acid metabolism, a spectrum of drugs for their treatment, and the occurrence of drug resistance. These parasites possess metabolic pathways that are divergent from those of their mammalian hosts and are often considered to be good targets for drug development. Sulfur-containing-amino-acid metabolism represents one such divergent metabolic pathway, namely, the cysteine biosynthetic pathway and methionine gamma-lyase-mediated catabolism of sulfur-containing amino acids, which are present in T. vaginalis and E. histolytica but absent in G. intestinalis. These pathways are potentially exploitable for development of drugs against amoebiasis and trichomoniasis. For instance, L-trifluoromethionine, which is catalyzed by methionine gamma-lyase and produces a toxic product, is effective against T. vaginalis and E. histolytica parasites in vitro and in vivo and may represent a good lead compound. In this review, we summarize the biology of these microaerophilic parasites, their clinical manifestation and epidemiology of disease, chemotherapeutics, the modes of action of representative drugs, and problems related to these drugs, including drug resistance. We further discuss our approach to exploit unique sulfur-containing-amino-acid metabolism, focusing on development of drugs against E. histolytica.
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Affiliation(s)
- Vahab Ali
- Department of Parasitology, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan
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9
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van der Giezen M, Tovar J, Clark CG. Mitochondrion‐Derived Organelles in Protists and Fungi. INTERNATIONAL REVIEW OF CYTOLOGY 2005; 244:175-225. [PMID: 16157181 DOI: 10.1016/s0074-7696(05)44005-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
The mitochondrion is generally considered to be a defining feature of eukaryotic cells, yet most anaerobic eukaryotes lack this organelle. Many of these were previously thought to derive from eukaryotes that diverged prior to acquisition of the organelle through endosymbiosis. It is now known that all extant eukaryotes are descended from an ancestor that had a mitochondrion and that in anaerobic eukaryotes the organelle has been modified into either hydrogenosomes, which continue to generate energy for the host cell, or mitosomes, which do not. These organelles have each arisen independently several times. Recent evidence suggests a shared derived characteristic that may be responsible for the retention of the organelles in the absence of the better-known mitochondrial functions--iron-sulfur cluster assembly. This review explores the events leading to this new understanding of mitochondrion-derived organelles in amitochondriate eukaryotes, the current state of our knowledge, and future areas for investigation.
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Affiliation(s)
- Mark van der Giezen
- School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey TW20 0EX, United Kingdom
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10
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Suchan P, Vyoral D, Petrák J, Šut'ák R, Rasoloson D, Nohýnková E, Doležal P, Tachezy J. Incorporation of iron into Tritrichomonas foetus cell compartments reveals ferredoxin as a major iron-binding protein in hydrogenosomes. MICROBIOLOGY (READING, ENGLAND) 2003; 149:1911-1921. [PMID: 12855742 DOI: 10.1099/mic.0.26122-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The intracellular transport of iron and its incorporation into organelles are poorly understood processes in eukaryotes and virtually unknown in parasitic protists. The transport of iron is of particular interest in trichomonads, which possess hydrogenosomes instead of mitochondria. The metabolic functions of hydrogenosomes, which contain a specific set of FeS proteins, entirely depend on iron acquisition. In this work the incorporation of iron into the cattle parasite Tritrichomonas foetus was monitored. Iron was efficiently taken up from (59)Fe-nitrilotriacetic acid and accumulated in the cytosol (88.9 %) and hydrogenosomes (4.7 % of the total radioactivity). Using atomic absorption spectrophotometry, an unusually high steady-state iron concentration in hydrogenosomes was determined [54.4+/-1.1 nmol Fe (mg protein)(-1)]. The concentration of iron in the cytosol was 13.4+/-0.5 nmol Fe (mg protein)(-1). Qualitative analysis of incorporated iron was performed using native gradient PAGE. The majority of the (59)Fe in the cytosol appeared as the labile-iron pool, which represents weakly bound iron associated with compounds of molecular mass ranging from 5000 to 30000 Da. Ferritin was not observed in Tt. foetus, nor in two other anaerobic protists, Entamoeba histolytica and Giardia intestinalis. Analysis of Tt. foetus hydrogenosomes showed at least nine iron-binding compounds, which were absent in metronidazole-resistant mutants. The major iron-binding compound was identified as [2Fe-2S] ferredoxin of the adrenodoxin type.
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Affiliation(s)
- Pavel Suchan
- Department of Parasitology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
| | - Daniel Vyoral
- Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 44, Prague 2, Czech Republic
| | - Jiří Petrák
- Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 44, Prague 2, Czech Republic
| | - Robert Šut'ák
- Department of Parasitology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
| | - Dominique Rasoloson
- Johns Hopkins University, Bloomberg School of Public Health, W. Harry Feinstone Department of Molecular Microbiology and Immunology, 615 North Wolfe Street, Baltimore 21205, MD, USA
| | - Eva Nohýnková
- Department of the Tropical Medicine, 1st Faculty of Medicine, Charles University, Faculty Hospital Bulovka, Studničkova 7, 128 00, Prague 2, Czech Republic
| | - Pavel Doležal
- Department of Parasitology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
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11
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Vidakovic M, Crossnoe CR, Neidre C, Kim K, Krause KL, Germanas JP. Reactivity of reduced [2Fe-2S] ferredoxins parallels host susceptibility to nitroimidazoles. Antimicrob Agents Chemother 2003; 47:302-8. [PMID: 12499206 PMCID: PMC149022 DOI: 10.1128/aac.47.1.302-308.2003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2002] [Revised: 08/20/2002] [Accepted: 10/01/2002] [Indexed: 11/20/2022] Open
Abstract
The kinetics of the electron transfer reaction between reduced [2Fe-2S] ferredoxins and select nitroimidazole antimicrobial agents is reported. The ferredoxins from the protozoan Trichomonas vaginalis and the cyanobacterium Anabaena sp. strain 7120 were studied because they are the proximal electron donors to nitroimidazoles in these two organisms with significantly different nitroimidazole susceptibilities. The rates of electron transfer from Anabaena ferredoxin to all nitroimidazoles were 1 to 2 orders of magnitude lower than for T. vaginalis ferredoxin. Quantitative structure-activity analysis of the kinetic data showed that the size of the alkyl substituent on the N-1 position of the imidazole ring strongly influenced the magnitude of the electron transfer rate constant. This implies that the distance between the iron-sulfur cluster and the nitro group of the imidazole is the critical variable in determining the rate of electron transfer. A correlation between the magnitude of the one-electron transfer rate constant with the susceptibility of the host organism to the cytotoxic effects of nitroimidazoles was also discovered. These results demonstrate that reductive activation is the most crucial step in determining the toxicity of nitroimidazoles.
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Affiliation(s)
- Momcilo Vidakovic
- Department of Chemistry, University of Houston, Houston, Texas 77204, USA
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12
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Crossnoe CR, Germanas JP, LeMagueres P, Mustata G, Krause KL. The crystal structure of Trichomonas vaginalis ferredoxin provides insight into metronidazole activation. J Mol Biol 2002; 318:503-18. [PMID: 12051855 DOI: 10.1016/s0022-2836(02)00051-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Crystallographic studies revealing the three-dimensional structure of the oxidized form of the [2Fe-2S] ferredoxin from Trichomonas vaginalis (TvFd) are presented. TvFd, a member of the hydrogenosomal class of ferredoxins, possesses a unique combination of redox and spectroscopic properties, and is believed to be the biological molecule that activates the drug metronidazole reductively in the treatment of trichomoniasis. It is the first hydrogenosomal ferredoxin to have its structure determined. The structure of TvFd reveals a monomeric, 93 residue protein with a fold similar to that of other known [2Fe-2S] ferredoxins. It contains nine hydrogen bonds to the sulfur atoms of the cluster, which is more than the number predicted on the basis of the spectroscopic data. The TvFd structure contains a large dipole moment like adrenodoxin, and appears to have a similar interaction domain. Our analysis demonstrates that TvFd has a unique cavity near the iron-sulfur cluster that exposes one of the inorganic sulfur atoms of the cluster to solvent. This cavity is not seen in any other [2Fe-2S] ferredoxin with known structure, and is hypothesized to be responsible for the high rate of metronidazole reduction by TvFd.
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Affiliation(s)
- Chetlen R Crossnoe
- Structural and Computational Biology and Molecular Biophysics Program, Baylor College of Medicine, Houston, TX 77030, USA
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13
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Vanácová S, Rasoloson D, Rázga J, Hrdý I, Kulda J, Tachezy J. Iron-induced changes in pyruvate metabolism of Tritrichomonas foetus and involvement of iron in expression of hydrogenosomal proteins. MICROBIOLOGY (READING, ENGLAND) 2001; 147:53-62. [PMID: 11160800 DOI: 10.1099/00221287-147-1-53] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The main function of the hydrogenosome, a typical organelle of trichomonads, is to convert malate or pyruvate to H(2), CO(2) and acetate by a pathway associated with ATP synthesis. This pathway relies on activity of iron-sulfur proteins such as pyruvate:ferredoxin oxidoreductase (PFOR), hydrogenase and ferredoxin. To examine the effect of iron availability on proper hydrogenosomal function, the metabolic activity of the hydrogenosome and expression of hydrogenosomal enzymes were compared in Tritrichomonas foetus maintained under iron-rich (150 microM iron nitrilotriacetate) or iron-restricted (180 microM 2,2-dipyridyl) conditions in vitro. The activities of PFOR and hydrogenase, and also production of acetate and H(2), were markedly decreased or absent in iron-restricted trichomonads. Moreover, a decrease in activity of the hydrogenosomal malic enzyme, which is a non-Fe-S protein, was also observed. Impaired function of hydrogenosomes under iron-restricted conditions was compensated for by activation of the cytosolic pathway, mediating conversion of pyruvate to ethanol via acetaldehyde. This metabolic switch was fully reversible. Production of hydrogen by iron-restricted trichomonads was restored to the level of organisms grown under iron-rich conditions within 3 h after addition of 150 microM iron nitrilotriacetate. Protein analysis of purified hydrogenosomes from iron-restricted cells showed decreased levels of proteins corresponding to PFOR, malic enzyme and ferredoxin. Accordingly, these cells displayed decreased steady-state level and synthesis of mRNAs encoding PFOR and hydrogenosomal malic enzyme. These data demonstrate that iron is essential for function of the hydrogenosome, show its involvement in the expression of hydrogenosomal proteins and indicate the presence of iron-dependent control of gene transcription in Tt. foetus.
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Affiliation(s)
- S Vanácová
- Department of Parasitology, Faculty of Science, Charles University, Vinicná 7, Prague, 128 44, Czech Republic
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14
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Abstract
Trichomonas vaginalis and Tritrichomonas foetus are sexually transmitted pathogens of the genito-urinary tract of humans and cattle, respectively. These organisms are amitochondrial anaerobes possessing hydrogenosomes, double membrane-bound organelles involved in catabolic processes extending glycolysis. The oxidative decarboxylation of pyruvate in hydrogenosomes is coupled to ATP synthesis and linked to ferredoxin-mediated electron transport. This pathway is responsible for metabolic activation of 5-nitroimidazole drugs, such as metronidazole, used in chemotherapy of trichomoniasis. Prolonged cultivation of trichomonads under sublethal pressure of metronidazole results in development of drug resistance. In both pathogenic species the resistance develops in a multistep process involving a sequence of stages that differ in drug susceptibility and metabolic activities. Aerobic resistance, similar to that occurring in clinical isolates of T. vaginalis from treatment-refractory patients, appears as the earliest stage. The terminal stage is characterised by stable anaerobic resistance at which the parasites show very high levels of minimal lethal concentration for metronidazole under anaerobic conditions (approximately 1000 microg ml(-1)). The key event in the development of resistance is progressive decrease and eventual loss of the pyruvate:ferredoxin oxidoreductase so that the drug-activating process is averted. In T. vaginalis at least, the development of resistance is also accompanied by decreased expression of ferredoxin. The pyruvate:ferredoxin oxidoreductase deficiency completely precludes metronidazole activation in T. foetus, while T. vaginalis possesses an additional drug-activating system which must be eliminated before the full resistance is acquired. This alternative pathway involves the hydrogenosomal malic enzyme and NAD:ferredoxin oxidoreductase. Metronidazole-resistant trichomonads compensate for the hydrogenosomal deficiency by an increased rate of glycolysis and by changes in their cytosolic pathways. Trichomonas vaginalis enhances lactate fermentation while T. foetus activates pyruvate conversion to ethanol. Drug-resistant T. foetus also increases activity of the cytosolic NADP-dependent malic enzyme, to enhance the pyruvate producing bypass and provide NADPH required by alcohol dehydrogenase. Production of succinate by this species is abolished. Metabolic changes accompanying in-vitro development of metronidazole resistance demonstrate the versatility of trichomonad metabolism and provide an interesting example of how unicellular eukaryotes can adjust their metabolism in response to the pressure of an unfavorable environment.
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Affiliation(s)
- J Kulda
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic.
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15
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Brown DM, Upcroft JA, Dodd HN, Chen N, Upcroft P. Alternative 2-keto acid oxidoreductase activities in Trichomonas vaginalis. Mol Biochem Parasitol 1999; 98:203-14. [PMID: 10080389 DOI: 10.1016/s0166-6851(98)00169-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We have induced high levels of resistance to metronidazole (1 mM or 170 microg ml(-1)) in two different strains of Trichomonas vaginalis (BRIS/92/STDL/F1623 and BRIS/92/STDL/B7708) and have used one strain to identify two alternative T. vaginalis 2-keto acid oxidoreductases (KOR) both of which are distinct from the already characterised pyruvate:ferredoxin oxidoreductase (PFOR). Unlike the characterised PFOR which is severely down-regulated in metronidazole-resistant parasites, both of the alternative KORs are fully active in metronidazole-resistant T. vaginalis. The first, KORI, localized in all membrane fractions but predominantly in the hydrogenosome fraction, is soluble in Triton X-100 and the second, KOR2, is extractable in 1 M acetate from membrane fractions of metronidazole-resistant parasites. PFOR and both KORI and KOR2 use a broad range of 2-keto acids as substrates (pyruvate, alpha-ketobutyrate, alpha-ketomalonate), including the deaminated forms of aromatic amino acids (indolepyruvate and phenylpyruvate). However, unlike PFOR neither KORI or KOR2 was able to use oz-ketoglutarate. Deaminated forms of branched chain amino acids (alpha-ketoisovalerate) were not substrates for T. vaginalis KORs. Since KOR I and KOR2 do not apparently donate electrons to ferredoxin, and are not down-regulated in metronidazole-resistant parasites, we propose that KORI and KOR2 provide metronidazole-resistant parasites with an alternative energy production pathway(s) which circumvents metronidazole activation.
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Affiliation(s)
- D M Brown
- Queensland Institute of Medical Research, The Bancroft Centre, Australia
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16
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Liu HY, Germanas JP. NMR spectroscopic studies of the hydrogenosomal [2Fe-2S] ferredoxin from Trichomonas vaginalis: hyperfine-shifted 1H resonances. J Inorg Biochem 1998; 72:127-31. [PMID: 10065531 DOI: 10.1016/s0162-0134(98)10069-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The hyperfine-shifted 1H NMR resonances of oxidized and reduced Trichomonas vaginalis ferredoxin, a functionally unique [2Fe-2S] ferredoxin, have been studied. The oxidized protein spectrum displayed a pattern of six broad upfield-shifted resonances between 13 and 40 ppm with chemical shifts distinct from those of other [2Fe-2S] ferredoxins. All hyperfine 1H resonances of the oxidized ferredoxin displayed anti-Curie temperature dependences. Reduced T. vaginalis ferredoxin displayed hyperfine resonances both upfield and downfield of the diamagnetic region. These resonances showed Curie temperature dependences. Overall the hyperfine-shifted NMR spectrum of T. vaginalis ferredoxin, along with other spectroscopic properties, suggested different structural properties for the active center of oxidized hydrogenosomal ferredoxins from those of other [2Fe-2S] ferredoxins.
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Affiliation(s)
- H Y Liu
- Department of Chemistry, Stevens Institute of Technology, Hoboken, NJ 07030, USA
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17
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Brown DM, Upcroft JA, Edwards MR, Upcroft P. Anaerobic bacterial metabolism in the ancient eukaryote Giardia duodenalis. Int J Parasitol 1998; 28:149-64. [PMID: 9504342 DOI: 10.1016/s0020-7519(97)00172-0] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The protozoan parasite, Giardia duodenalis, shares many metabolic and genetic attributes of the bacteria, including fermentative energy metabolism which relies heavily on pyrophosphate rather than adenosine triphosphate and as a result contains two typically bacterial glycolytic enzymes which are pyrophosphate dependent. Pyruvate decarboxylation and subsequent electron transport to as yet unidentified anaerobic electron acceptors relies on a eubacterial-like pyruvate:ferredoxin oxidoreductase and an archaebacterial/eubacterial-like ferredoxin. The presence of another 2-ketoacid oxidoreductase (with a preference for alpha-ketobutyrate) and multiple ferredoxins in Giardia is also a trait shared with the anaerobic bacteria. Giardia pyruvate:ferredoxin oxidoreductase is distinct from the pyruvate dehydrogenase multienzyme complex invariably found in mitochondria. This is consistent with a lack of mitochondria, citric acid cycle, oxidative phosphorylation and glutathione in Giardia. Giardia duodenalis actively consumes oxygen and yet lacks the conventional mechanisms of oxidative stress management, including superoxide dismutase, catalase, peroxidase, and glutathione cycling, which are present in most eukaryotes. In their place Giardia contains a prokaryotic H2O-producing NADH oxidase, a membrane-associated NADH peroxidase, a broad-range prokaryotic thioredoxin reductase-like disulphide reductase and the low molecular weight thiols, cysteine, thioglycolate, sulphite and coenzyme A. NADH oxidase is a major component of the electron transport pathway of Giardia which, in conjunction with disulphide reductase, protects oxygen-labile proteins such as ferredoxin and pyruvate:ferredoxin oxidoreductase against oxidative stress by maintaining a reduced intracellular environment. As the terminal oxidase, NADH oxidase provides a means of removing excess H+, thereby enabling continued pyruvate decarboxylation and the resultant production of acetate and adenosine triphosphate. A further example of the bacterial-like metabolism of Giardia is the utilisation of the amino acid arginine as an energy source. Giardia contain the arginine dihydrolase pathway, which occurs in a number of anaerobic prokaryotes, but not in other eukaryotes apart from trichomonads and Chlamydomonas reinhardtii. The pathway includes substrate level phosphorylation and is sufficiently active to make a major contribution to adenosine triphosphate production. Two enzymes of the pathway, arginine deiminase and carbamate kinase, are rare in eukaryotes and do not occur in higher animals. Arginine is transported into the trophozoite via a bacterial-like arginine:ornithine antiport. Together these metabolic pathways in Giardia provide a wide range of potential drug targets for future consideration.
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Affiliation(s)
- D M Brown
- Queensland Institute of Medical Research, The Bancroft Centre, Brisbane, Australia
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18
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Lactate dehydrogenase from the protozoan parasite, Trichomonas vaginalis. Comp Biochem Physiol B Biochem Mol Biol 1996. [DOI: 10.1016/s0305-0491(96)00164-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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19
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Vidakovic M, Germanas JP. Electrostatic effects in electron transfer reactions of [2Fe-2S] ferredoxins with inorganic reagents. Protein Sci 1996; 5:1793-9. [PMID: 8880903 PMCID: PMC2143536 DOI: 10.1002/pro.5560050905] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The kinetics of electron transfer from the reduced [2Fe-2S] ferredoxins from the cyanobacterium Anabaena 7120 and the protozoan Trichomonas vaginalis to select cobalt coordination compounds have been studied in order to gain insight into the mechanism of electron transfer and intrinsic reactivity of [2Fe-2S] active sites. With tripositive cobalt complexes, reactions of both proteins displayed saturation kinetics; values of association constants of 12,900 and 1,400 M-1 and limiting rate constants of 7.6 and 3.5 s-1 were found for oxidation of T. vaginalis and Anabaena ferredoxins, respectively, by Co(NH3)6(3+) at room temperature and I = 0.1 M. An activation enthalpy of 12.1 kcal/mol and activation entropy of -14.3 cal/mol K for oxidation of T. vaginalis ferredoxin by Co(NH3)6(3+) contrasted with corresponding values of 13.4 kcal/mol and -10.5 cal/mol K for the Spirulina platensis protein, which is homologous to Anabaena ferredoxin. The dependence of the reaction rates on ionic strength were measured to probe the importance of electrostatics on the reactivity of the proteins. Analysis of the ionic strength dependence of the oxidation of the proteins by Co(NH3)6(3+) by the "parallel plate" model of Watkins et al. (1994, Protein Sci 3:2104-2114) afforded values for active site charges of -0.7 and -1.1 and limiting rate constants at infinite ionic strength of 25,800 and 76 M-1 S-1 for T. vaginalis and Anabaena ferredoxins, respectively. These results suggest that the [2Fe-2S] center of the protozoal ferredoxin is more accessible and adjacent to a less highly charged, more compact patch of negative charges than the photosynthetic protein.
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Affiliation(s)
- M Vidakovic
- Department of Chemistry, University of Houston, Texas 77204-5641, USA
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20
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Quon DV, Delgadillo MG, Johnson PJ. Transcription in the early diverging eukaryote Trichomonas vaginalis: an unusual RNA polymerase II and alpha-amanitin-resistant transcription of protein-coding genes. J Mol Evol 1996; 43:253-62. [PMID: 8703091 DOI: 10.1007/bf02338833] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We have examined transcription in an early diverging eukaryote by analyzing the effect of the fungus-derived toxin alpha-amanitin on the transcription of protein-coding genes of the protist Trichomonas vaginalis. In contrast to that typical in eukaryotes, the RNA polymerase that transcribes T. vaginalis protein-coding genes is relatively resistant to alpha-amanitin (50% inhibition = 250 microg alpha-amanitin/ml). We have also characterized the gene encoding the largest subunit of RNA polymerase II, the subunit that binds alpha-amanitin. This protein is 41% identical to the mouse RNA polymerase II. Sequence analysis of the 50-amino-acid region thought to bind alpha-amanitin shows that this region of the trichomonad RNA polymerase II lacks many of the conserved amino acids present in the putative binding site, in agreement with the observed insensitivity to this inhibitor. Similar to other RNA polymerase IIs analyzed from ancient eukaryotes, the T. vaginalis RNA polymerase II lacks the typical heptapeptide (Tyr-Ser-Pro-Thr-Ser-Pro-Ser) repeat carboxyl-terminal domain (CTD) that is a hallmark of higher eukaryotic RNA polymerase IIs. The trichomonad enzyme, however, does contain a short modified CTD that is rich in the amino acid residues that compose the repeat. These data suggest that T. vaginalis protein-coding genes are transcribed by a RNA polymerase II that is relatively insensitive to alpha-amanitin and that differs from typical eukaryotic RNA polymerase IIs as it lacks a heptapeptide repeated CTD.
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Affiliation(s)
- D V Quon
- Department of Microbiology and Immunology, School of Medicine, University of California, Los Angeles, 90095-1747, USA
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21
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Vidakovic MS, Fraczkiewicz G, Germanas JP. Expression and spectroscopic characterization of the hydrogenosomal [2Fe-2S] ferredoxin from the protozoan Trichomonas vaginalis. J Biol Chem 1996; 271:14734-9. [PMID: 8663034 DOI: 10.1074/jbc.271.25.14734] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The heterologous expression and spectroscopic characterization of the [2Fe-2S] ferredoxin from the sexually transmitted human parasite Trichomonas vaginalis is described. Using oligonucleotide primers based on the deduced DNA sequence, the gene encoding the ferredoxin was amplified by polymerase chain reaction and cloned into a T7 RNA polymerase expression vector. Expression of the gene in Escherichia coli host HMS174(DE3) resulted in the high level production of the protein with the correctly assembled iron-sulfur cluster. The absorption, circular dichroism, resonance Raman, and EPR spectra of the recombinant protein revealed many differences from those of other [2Fe-2S] ferredoxins. The redox potential of the protein (-347 mV versus normal hydrogen electrode) was also determined. Whereas the amino acid sequence of T. vaginalis ferredoxin showed greatest homology to the [2Fe-2S] ferredoxins found in bacteria and vertebrate mitochondria which function in cytochrome P450 oxidation pathways, the spectroscopic properties showed substantial dissimilarity. Differences in the biophysical properties and function of T. vaginalis ferredoxin are proposed to result from the characteristic amino acid sequence of the parasite protein near the cysteine residues that ligate the valence-localized Fe(III) site of the reduced cluster.
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Affiliation(s)
- M S Vidakovic
- Department of Chemistry, University of Houston, Houston, Texas 77204-5641, USA
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22
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Primary structure and eubacterial relationships of the pyruvate:Ferredoxin oxidoreductase of the amitochondriate eukaryoteTrichomonas vaginalis. J Mol Evol 1995. [DOI: 10.1007/bf01215186] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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23
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Lahti CJ, Bradley PJ, Johnson PJ. Molecular characterization of the alpha-subunit of Trichomonas vaginalis hydrogenosomal succinyl CoA synthetase. Mol Biochem Parasitol 1994; 66:309-18. [PMID: 7808480 DOI: 10.1016/0166-6851(94)90157-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The anaerobic, parasitic protist, Trichomonas vaginalis, is characterized by the absence of mitochondria and the presence of double membrane bound organelles called hydrogenosomes. Succinyl-coenzyme A synthetase is a hydrogenosomal enzyme which catalyzes the formation of ATP via substrate-level phosphorylation. We have characterized genes encoding the alpha subunit of the hydrogenosomal protein succinyl-coenzyme A synthetase (SCS). The alpha-SCS of T. vaginalis is encoded by a multigene family composed of 3 similar genes that do not appear allelic. These 3 alpha-SCS genes encode a protein with a calculated molecular mass of approximately 32.5 kDa that has > 50% identity (> 70% similarity with alpha-SCSs from Escherichia coli, Thermus flavus, and rat liver mitochondria. Antibodies raised against recombinant T vaginalis alpha-SCS expressed in bacteria were used to isolate alpha-SCS proteins from purified hydrogenosomes. These proteins partition into the soluble fraction of hydrogenosomes treated with sodium carbonate at high pH, consistent with a matrix localization in the organelle. Amino-terminal sequencing of purified alpha-SCS proteins shows that mature proteins lack a short, leader sequence of 9 amino acids. These amino terminal sequences which are cleaved from T. vaginalis alpha-SCSs are similar to each other and to all other leader sequences identifed on hydrogenosomal proteins.
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Affiliation(s)
- C J Lahti
- Department of Microbiology and Immunology, University of California, Los Angeles, 90024-1747
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24
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Johnson PJ, Schuck BL, Delgadillo MG. Analysis of a single-domain P-glycoprotein-like gene in the early-diverging protist Trichomonas vaginalis. Mol Biochem Parasitol 1994; 66:127-37. [PMID: 7984175 DOI: 10.1016/0166-6851(94)90043-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We have characterized a gene encoding an Adenosine triphosphate (ATP) Binding Cassette (ABC) transmembrane protein from Trichomonas vaginalis, an early-diverging protozoan parasite. This gene, Tvpgp1, encodes a 589-amino acid protein with an amino-terminal hydrophobic region, 6 potential membrane-spanning segments and a carboxy-terminal ATP binding site. Tvpgp1 is most similar in sequence to mammalian P-glycoproteins, 170 kDa transport proteins which are frequently overexpressed in multiple drug-resistant (Mdr) tumor cell lines. However, Tvpgp1 is half the size of typical P-glycoproteins which are tandem duplications. These data suggest that the duplication/fusion events which gave rise to the bipartite structure comprised of 2 similar halves which characterize eukaryotic P-glycoproteins may have occurred after the divergence of trichomonads (Parabasalia) from the main line of eukaryotic evolutionary descent. We have examined 7 metronidazole resistant strains of T. vaginalis to determine whether the Tvpgp1 gene is overexpressed or amplified. 2 drug resistant strains show a 2-3-fold overexpression and one shows a 20-fold overexpression of Tvpgp mRNA. The gene is not amplified in any of the drug resistant strains. On the contrary, 4 of the 7 resistant strains lack one of 2 Tvpgp genes found in drug-sensitive strains.
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Affiliation(s)
- P J Johnson
- Department of Microbiology and Immunology, School of Medicine, University of California, Los Angeles 90024-1747
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25
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Townson SM, Hanson GR, Upcroft JA, Upcroft P. A purified ferredoxin from Giardia duodenalis. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 220:439-46. [PMID: 8125101 DOI: 10.1111/j.1432-1033.1994.tb18641.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A ferredoxin has been purified to homogeneity from the ancient protozoan parasite Giardia duodenalis. As far as we know, this is the first electron transport protein to be characterised from the organism. The ferredoxin exhibits absorption maxima at 296 and 406 nm with molar absorption coefficients of epsilon 296 = 16,650 +/- 240 M-1 cm-1 and epsilon 406 = 13,100 +/- 370 M-1 cm-1 respectively. The A406/A296 ratio ranged over 0.78-0.82. The molecular mass of the apoprotein calculated by mass spectrometry was 5730 +/- 100Da and the minimum molecular mass by amino acid analysis was 5926Da. There were four cysteine residues/molecule protein but no methionine, arginine, histidine or tyrosine. The absence of these latter residues is consistent with the amino acid content of most ferredoxins. The N-terminal amino acid sequence exhibited greatest similarity to Desulfovibrio gigas ferredoxin II and indicated the potential to coordinate an iron-sulfur cluster. There were 3.21 +/- 0.41 mol sulfide and 2.65 +/- 0.06 mol iron/mol protein. Electron paramagnetic resonance studies of this protein have indicated the presence of an iron-sulfur centre consistent with those of known ferredoxins. Ferredoxin serves as a biological electron acceptor from giardial pyruvate dehydrogenase with metronidazole as a terminal electron acceptor. Such a pathway may serve as a possible mechanism for the reductive activation of metronidazole in this parasite. A second ferredoxin has been purified to homogeneity, but at this stage there is insufficient material to fully characterise this protein. No other low-molecular-mass electron transport proteins have been identified in Giardia under the growth conditions described.
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Affiliation(s)
- S M Townson
- Queensland Institute of Medical Research, Bancroft Center, Brisbane, Australia
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26
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Ellis JE, Williams R, Cole D, Cammack R, Lloyd D. Electron transport components of the parasitic protozoon Giardia lamblia. FEBS Lett 1993; 325:196-200. [PMID: 8391475 DOI: 10.1016/0014-5793(93)81072-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The energy metabolism of the intestinal parasite, Giardia lamblia, involves the iron-sulphur protein, pyruvate:ferredoxin oxidoreductase. Cell fractionation studies showed that this enzyme is associated with the membranes. NADH and NADPH dehydrogenases were found in both the membrane and cytosolic fractions. EPR spectroscopic studies showed the presence of iron-sulphur clusters in the membrane fraction and in the cytosolic fraction, non-sedimentable at 6 x 10(6) g.min. An acidic, soluble protein fraction was separated from the cytosol. It had an EPR spectrum in the reduced state, characteristic of the 2[4Fe-4S] type of ferredoxin, with g-factors at 2.04. 1.93 and 1.89, and the midpoint redox potential was estimated to be -360 mV. This species is probably a ferredoxin, like those of anaerobic bacteria such as Clostridium and Desulfovibrio spp. and also that of Entamoeba histolytica. The protein was readily and irreversibly oxidized to give [3Fe-4S] clusters.
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Affiliation(s)
- J E Ellis
- Microbiology Group, School of Pure and Applied Biology, University of Wales College of Cardiff, UK
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27
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Williams AG, Lloyd D. Biological Activities of Symbiotic and Parasitic Protozoa and Fungi in Low-Oxygen Environments. ADVANCES IN MICROBIAL ECOLOGY 1993. [DOI: 10.1007/978-1-4615-2858-6_5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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28
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Lahti CJ, d'Oliveira CE, Johnson PJ. Beta-succinyl-coenzyme A synthetase from Trichomonas vaginalis is a soluble hydrogenosomal protein with an amino-terminal sequence that resembles mitochondrial presequences. J Bacteriol 1992; 174:6822-30. [PMID: 1400232 PMCID: PMC207358 DOI: 10.1128/jb.174.21.6822-6830.1992] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
We describe studies directed toward understanding the biogenesis and origin of the hydrogenosome, an unusual organelle found exclusively in certain anaerobic eukaryotes that lack mitochondria. Hydrogenosomes are involved in fermentative carbohydrate metabolism and are proposed to have arisen through conversion of mitochondria or via endosymbiosis with an anaerobic bacterium. We cloned a gene encoding the beta subunit of the hydrogenosomal protein succinyl-coenzyme A synthetase (beta-SCS) and isolated the protein from Trichomonas vaginalis. The T. vaginalis beta-SCS gene encodes a protein with a calculated molecular mass of 43,980 Da that has 43% amino acid identity (65% similarity) with beta-SCS from Escherichia coli. The trichomonad protein partitions into the soluble fraction of hydrogenosomes treated with sodium carbonate at high pH, consistent with a matrix localization within the organelle. The protein is encoded by a multigene family composed of at least three members. Amino-terminal sequencing of beta-SCS purified from T. vaginalis hydrogenosomes shows that the mature protein lacks the first nine amino acids encoded in the gene. This apparent amino-terminal leader sequence is strikingly similar to that of another hydrogenosomal protein and to mitochondrial presequences.
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Affiliation(s)
- C J Lahti
- Department of Microbiology and Immunology, University of California, Los Angeles 90024-1747
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29
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30
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Matsubara H, Saeki K. Structural and Functional Diversity of Ferredoxins and Related Proteins. ADVANCES IN INORGANIC CHEMISTRY 1992. [DOI: 10.1016/s0898-8838(08)60065-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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31
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Müller M. Energy metabolism of ancestral eukaryotes: a hypothesis based on the biochemistry of amitochondriate parasitic protists. Biosystems 1992; 28:33-40. [PMID: 1292665 DOI: 10.1016/0303-2647(92)90005-j] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Parasitic amitochondriate protists, representatives of early branches of eukaryote evolution, differ considerably in their central, energy metabolism from mitochondrion-bearing cells. These differences are: significant metabolic functions of inorganic pyrophosphate, major role of iron-sulfur proteins in key metabolic steps and in hydrogenosome-bearing organisms the disposal of electrons by H2 formation. Cytochrome-mediated electron transport and electron transport-linked phosphorylation are absent. All proteins which have been sequenced so far were found to be homologous to isofunctional proteins from other organisms. A few reactions, however, are catabolized by proteins which are not homologous to enzymes performing similar reactions in other eukaryotes. Two significantly different types of metabolism of amitochondriate protists can be distinguished: (a) without compartmentation and (b) with cytosol/hydrogenosome compartmentation. It is likely that these metabolic types have conserved certain traits present in ancestral eukaryotes before mitochondria became established.
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Affiliation(s)
- M Müller
- Rockefeller University, New York, New York 10021
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32
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Lahti CJ, Johnson PJ. Trichomonas vaginalis hydrogenosomal proteins are synthesized on free polyribosomes and may undergo processing upon maturation. Mol Biochem Parasitol 1991; 46:307-10. [PMID: 1922201 DOI: 10.1016/0166-6851(91)90055-b] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- C J Lahti
- Department of Microbiology and Immunology, UCLA School of Medicine 90024-1747
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Abstract
Over the last few years a remarkable progress has been made in the understanding of parasites biochemistry, molecular biology, and immunology. This progress is especially encouraging in that emphasis on drug development is shifting from random screening towards a more rational approach. A number of peculiar aspects characteristic of parasites which are not present in other organisms and that might be exploitable for the design of specific agents have been described recently. One of these aspects is their deficiency in defense mechanisms against oxygen toxicity. Catalase is absent in many parasites. Distinct superoxide dismutases have been detected and specific inhibitors of these enzymes have been investigated. Glutathione is absent in some anaerobic protozoa. Peroxidase and reductase activities dependent on a glutathione-spermidine cofactor termed trypanothione have been detected in several trypanosomatids and apparently replace the glutathione peroxidase-glutathione reductase system of other eukaryotic cells. Free radical intermediates have been shown to be involved in the reaction of enzymes present in anaerobic protozoa. In addition, a number of antiparasitic agents have been shown to exert their actions through a free radical metabolism: nitro compounds used against trypanosomatids, anaerobic protozoa and helminths; crystal violet used in blood banks to prevent blood transmission of Chagas' disease; the antimalarial primaquine, chloroquinine, and quinhasou; and quinones active in vitro and in vivo against different parasites.
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Affiliation(s)
- R Docampo
- Rockerfeller University, New York, NY 10021
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34
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Free radical intermediates in the reaction of pyruvate:ferredoxin oxidoreductase in Tritrichomonas foetus hydrogenosomes. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)45219-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Meyer J, Bruschi MH, Bonicel JJ, Bovier-Lapierre GE. Amino acid sequence of [2Fe-2S] ferredoxin from Clostridium pasteurianum. Biochemistry 1986; 25:6054-61. [PMID: 3790505 DOI: 10.1021/bi00368a033] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The complete amino acid sequence of the [2Fe-2S] ferredoxin from the saccharolytic anaerobe Clostridium pasteurianum has been determined by automated Edman degradation of the whole protein and of peptides obtained by tryptic and by staphylococcal protease digestion. The polypeptide chain consists of 102 amino acids, including 5 cysteine residues in positions 11, 14, 24, 56, and 60. The sequence has been analyzed for hydrophilicity and for secondary structure predictions. In its native state the protein is a dimer, each subunit containing one [2Fe-2S] cluster, and it has a molecular weight of 23,174, including the four iron and inorganic sulfur atoms. The extinction coefficient of the native protein is 19,400 M-1 cm-1 at 463 nm. The positions of the cysteine residues, four of which are most probably the ligands of the [2Fe-2S] cluster, on the polypeptide chain of this protein are very different from those found in other [2Fe-2S] proteins, and in other ferredoxins in general. In addition, whole sequence comparisons of the [2Fe-2S] ferredoxin from C. pasteurianum with a number of other ferredoxins did not reveal any significant homologies. The likely occurrence of several phylogenetically unrelated ferredoxin families is discussed in the light of these observations.
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Steinbüchel A, Müller M. Anaerobic pyruvate metabolism of Tritrichomonas foetus and Trichomonas vaginalis hydrogenosomes. Mol Biochem Parasitol 1986; 20:57-65. [PMID: 3090435 DOI: 10.1016/0166-6851(86)90142-8] [Citation(s) in RCA: 102] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Hydrogenosomes isolated from Tritrichomonas foetus and Trichomonas vaginalis fermented pyruvate to acetate, malate, H2, and CO2 in an anaerobic process dependent on ADP, Pi, Mg2+, and succinate. The extent to which pyruvate was carboxylated to malate by malate dehydrogenase (decarboxylating) rather than decarboxylated to acetate by pyruvate/ferredoxin oxidoreductase was dependent on pCO2. The processes observed showed carbon and redox balances. The presence of an NADH/ferredoxin oxidoreductase activity was demonstrated. This enzyme is likely to be involved in the transfer of electrons from the ferredoxin reduced in pyruvate oxidation to NAD+ needed for the reductive carboxylation of pyruvate. Disruption of hydrogenosomes with Triton X-100 led to cessation of pyruvate-dependent H2 formation which could be restored by addition of coenzyme A and methyl viologen or ferredoxin. The formation of acetate and H2 by undisrupted hydrogenosomes proceeded at approximately half maximal rates in the presence of 25 microM succinate for T. foetus and 5 microM succinate for T. vaginalis. The apparent Km value of the acetate/succinate CoA transferase from T. foetus for succinate was approximately 45 microM, thus the stimulating effect of succinate might be due to the requirement of this enzyme for succinate. The exact mechanism of this effect remains to be elucidated, however.
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Chapman A, Cammack R, Linstead DJ, Lloyd D. Respiration of Trichomonas vaginalis. Components detected by electron paramagnetic resonance spectroscopy. EUROPEAN JOURNAL OF BIOCHEMISTRY 1986; 156:193-8. [PMID: 3007142 DOI: 10.1111/j.1432-1033.1986.tb09567.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Chapman A, Linstead DJ, Lloyd D, Williams J. 13C-NMR reveals glycerol as an unexpected major metabolite of the protozoan parasite Trichomonas vaginalis. FEBS Lett 1985; 191:287-92. [PMID: 3876951 DOI: 10.1016/0014-5793(85)80026-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
13C-NMR has been used to study the kinetics of the formation of metabolites from [1-13C]glucose in intact cells of Trichomonas vaginalis during anaerobic incubation. As well as the expected metabolites lactate and acetate, this technique revealed glycerol as an additional major product, present in amounts equimolar with acetate. The formation of glycerol is readily explained in terms of the need to maintain redox balance. This protozoan now joins the small group of organisms which are known to produce glycerol as a result of normal metabolic activities.
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Gorrell TE. Effect of culture medium iron content on the biochemical composition and metabolism of Trichomonas vaginalis. J Bacteriol 1985; 161:1228-30. [PMID: 3871763 PMCID: PMC215033 DOI: 10.1128/jb.161.3.1228-1230.1985] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Trichomonas vaginalis grown in iron-enriched medium contained increased concentrations of iron-sulfur proteins, including ferredoxin and pyruvate-ferredoxin oxidoreductase. The increases in hydrogenosomal constituents correlated with increased in vivo hydrogenosomal metabolism.
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