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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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Dhamodharan R, Hoti SL, Sankari T. Characterization of cofactor-independent phosphoglycerate mutase isoform-1 (Wb-iPGM) gene: a drug and diagnostic target from human lymphatic filarial parasite, Wuchereria bancrofti. INFECTION GENETICS AND EVOLUTION 2012; 12:957-65. [PMID: 22386851 DOI: 10.1016/j.meegid.2012.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 01/25/2012] [Accepted: 02/13/2012] [Indexed: 11/18/2022]
Abstract
The inter-conversion of 3-phosphoglycerate and 2-phosphoglycerate during glycolysis and gluconeogenesis in filarial nematodes, is catalyzed by a co-factor-independent phosphoglycerate mutase (iPGM). The gene encoding iPGM isoform-1 was amplified from Wuchereria bancrofti, the major causative agent of human lymphatic filariasis. Partial genomic DNA (gDNA) fragment of the gene was also amplified from periodic and sub-periodic forms of W. bancrofti and Brugia malayi and sequenced. The Wb-iPGM isoform-1 gene encodes an ORF of 515 amino acids and is found to share 99.4%, 96.0%, and 64.0% amino acid sequence identity with iPGM of B. malayi, Onchocerca volvulus, and Caenorhabditis elegans, respectively. Serine and all the other 13 amino acid residues involved in the catalytic function of iPGM are highly conserved. Further comparison of iPGM nucleotide and amino acid sequences of Wolbachia of B. malayi with Wb-iPGM showed 41% and 54.4% similarity, respectively. The analysis of partial genomic and amino acid sequences and phylogenetic tree of Wb-iPGM indicated that this gene, apart from being a potential drug target, could provide diagnostic, taxonomical, and evolutionary markers. This is the first report of the characterization of iPGM gene from W. bancrofti.
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Affiliation(s)
- R Dhamodharan
- Vector Control Research Centre (ICMR), Indira Nagar, Puducherry 605 006, India
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53
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Lavorato SN, Andrade SF, Silva THA, Alves RJ, Oliveira RB. Phosphofructokinase: structural and functional aspects and design of selective inhibitors. MEDCHEMCOMM 2012. [DOI: 10.1039/c2md20122d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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54
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Enlightening the molecular basis of trypanothione specificity in trypanosomatids: Mutagenesis of Leishmania infantum glyoxalase II. Exp Parasitol 2011; 129:402-8. [DOI: 10.1016/j.exppara.2011.08.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 08/03/2011] [Accepted: 08/08/2011] [Indexed: 11/24/2022]
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Gualdrón-López M, Brennand A, Hannaert V, Quiñones W, Cáceres AJ, Bringaud F, Concepción JL, Michels PAM. When, how and why glycolysis became compartmentalised in the Kinetoplastea. A new look at an ancient organelle. Int J Parasitol 2011; 42:1-20. [PMID: 22142562 DOI: 10.1016/j.ijpara.2011.10.007] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 10/13/2011] [Accepted: 10/14/2011] [Indexed: 12/21/2022]
Abstract
A characteristic, well-studied feature of the pathogenic protists belonging to the family Trypanosomatidae is the compartmentalisation of the major part of the glycolytic pathway in peroxisome-like organelles, hence designated glycosomes. Such organelles containing glycolytic enzymes appear to be present in all members of the Kinetoplastea studied, and have recently also been detected in a representative of the Diplonemida, but they are absent from the Euglenida. Glycosomes therefore probably originated in a free-living, common ancestor of the Kinetoplastea and Diplonemida. The initial sequestering of glycolytic enzymes inside peroxisomes may have been the result of a minor mistargeting of proteins, as generally observed in eukaryotic cells, followed by preservation and its further expansion due to the selective advantage of this specific form of metabolic compartmentalisation. This selective advantage may have been a largely increased metabolic flexibility, allowing the organisms to adapt more readily and efficiently to different environmental conditions. Further evolution of glycosomes involved, in different taxonomic lineages, the acquisition of additional enzymes and pathways - often participating in core metabolic processes - as well as the loss of others. The acquisitions may have been promoted by the sharing of cofactors and crucial metabolites between different pathways, thus coupling different redox processes and catabolic and anabolic pathways within the organelle. A notable loss from the Trypanosomatidae concerned a major part of the typical peroxisomal H(2)O(2)-linked metabolism. We propose that the compartmentalisation of major parts of the enzyme repertoire involved in energy, carbohydrate and lipid metabolism has contributed to the multiple development of parasitism, and its elaboration to complicated life cycles involving consecutive different hosts, in the protists of the Kinetoplastea clade.
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Affiliation(s)
- Melisa Gualdrón-López
- Research Unit for Tropical Diseases, de Duve Institute and Laboratory of Biochemistry, Université catholique de Louvain, Avenue Hippocrate 74, Postal Box B1.74.01, B-1200 Brussels, Belgium
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56
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Trypanosomes and the solution to a 50-year mitochondrial calcium mystery. Trends Parasitol 2011; 28:31-7. [PMID: 22088944 DOI: 10.1016/j.pt.2011.10.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 10/19/2011] [Accepted: 10/19/2011] [Indexed: 12/29/2022]
Abstract
The ability of mitochondria to take up Ca(2+) was discovered 50 years ago. This calcium uptake, through a mitochondrial calcium uniporter (MCU), is important not only for the regulation of cellular ATP concentration but also for more complex pathways such as shaping Ca(2+) signals and the activation of programmed cell death. The molecular nature of the uniporter remained unknown for decades. By a comparative study of mitochondrial protein profiles of organisms lacking or possessing MCU, such as yeast in the former case and vertebrates and trypanosomes in the latter, two groups recently found the protein that possesses all the characteristics of the MCU. These results add another success story to the already substantial contributions of trypanosomes to mammalian biochemistry.
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Salavati R, Moshiri H, Kala S, Shateri Najafabadi H. Inhibitors of RNA editing as potential chemotherapeutics against trypanosomatid pathogens. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2011; 2:36-46. [PMID: 24533263 DOI: 10.1016/j.ijpddr.2011.10.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 10/17/2011] [Accepted: 10/21/2011] [Indexed: 01/14/2023]
Abstract
The related trypanosomatid pathogens, Trypanosoma brucei spp., Trypanosoma cruzi and Leishmania spp. cause devastating diseases in humans and animals and continue to pose a major challenge in drug development. Mitochondrial RNA editing, catalyzed by multi-protein complexes known as editosomes, has provided an opportunity for development of efficient and specific chemotherapeutic targets against trypanosomatid pathogens. This review will discuss both methods for discovery of RNA editing inhibitors, as well as inhibitors against the T. brucei editosome that were recently discovered through creative virtual and high throughput screening methods. In addition, the use of these inhibitors as agents that can block or perturb one or more steps of the RNA editing process will be discussed. These inhibitors can potentially be used to study the dynamic processing and assembly of the editosome proteins. A thorough understanding of the mechanisms and specificities of these new inhibitors is needed in order to contribute to both the functional studies of an essential gene expression mechanism and to the possibility of future drug development against the trypanosomatid pathogens.
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Affiliation(s)
- Reza Salavati
- Department of Biochemistry, McGill University, McIntyre Medical Building, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G1Y6 ; Institute of Parasitology, McGill University, 21111 Lakeshore Road, Ste. Anne de Bellevue, Quebec, Canada H9X3V9 ; McGill Centre for Bioinformatics, McGill University, Bellini Building, 3649 Promenade Sir William Osler, Montreal, Quebec, Canada H3G0B1
| | - Houtan Moshiri
- Department of Biochemistry, McGill University, McIntyre Medical Building, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G1Y6 ; Institute of Parasitology, McGill University, 21111 Lakeshore Road, Ste. Anne de Bellevue, Quebec, Canada H9X3V9
| | - Smriti Kala
- Institute of Parasitology, McGill University, 21111 Lakeshore Road, Ste. Anne de Bellevue, Quebec, Canada H9X3V9
| | - Hamed Shateri Najafabadi
- Institute of Parasitology, McGill University, 21111 Lakeshore Road, Ste. Anne de Bellevue, Quebec, Canada H9X3V9 ; McGill Centre for Bioinformatics, McGill University, Bellini Building, 3649 Promenade Sir William Osler, Montreal, Quebec, Canada H3G0B1
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Shah TD, Hickey MC, Capasso KE, Palenchar JB. The characterization of a unique Trypanosoma brucei β-hydroxybutyrate dehydrogenase. Mol Biochem Parasitol 2011; 179:100-6. [PMID: 21767577 DOI: 10.1016/j.molbiopara.2011.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 06/13/2011] [Accepted: 07/02/2011] [Indexed: 10/18/2022]
Abstract
A putative β-hydroxybutyrate dehydrogenase (βHBDH) ortholog was identified in Trypanosoma brucei, the unicellular eukaryotic parasite responsible for causing African Sleeping Sickness. The trypanosome enzyme has greater sequence similarity to bacterial sources of soluble βHBDH than to membrane-bound Type I βHBDH found in higher eukaryotes. The βHBDH gene was cloned from T. brucei genomic DNA and active, recombinant His-tagged enzyme (His(10)-TbβHBDH) was purified to approximate homogeneity from E. coli. βHBDH catalyzes the reversible NADH-dependent conversion of acetoacetate to D-3-hydroxybutyrate. In the direction of D-3-hydroxybutyrate formation, His(10)-TbβHBDH has a k(cat) value of 0.19 s(-1) and a K(M) value of 0.69 mM for acetoacetate. In the direction of acetoacetate formation, His(10)-TbβHBDH has a k(cat) value of 11.2 s(-1) and a K(M) value of 0.65 mM for D-3-hydroxybutyrate. Cofactor preference was examined and His(10)-TbβHBDH utilizes both NAD(H) and NADP(H) almost equivalently, distinguishing the parasite enzyme from other characterized βHBDHs. Furthermore, His(10)-TbβHBDH binds NAD(P)(+) in a cooperative fashion, another unique characteristic of trypanosome βHBDH. The apparent native molecular weight of recombinant His(10)-TbβHBDH is 112 kDa, corresponding to tetramer, as determined through size exclusion chromatography. RNA interference studies in procyclic trypanosomes were carried out to evaluate the importance of TbβHBDH in vivo. Upon knockdown of TbβHBDH, a small reduction in parasite growth was observed suggesting βHBDH has an important physiological role in T. brucei.
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Affiliation(s)
- Tina D Shah
- Department of Chemistry, Villanova University, Villanova, PA 19085, United States
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59
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Aphasizheva I, Maslov D, Wang X, Huang L, Aphasizhev R. Pentatricopeptide repeat proteins stimulate mRNA adenylation/uridylation to activate mitochondrial translation in trypanosomes. Mol Cell 2011; 42:106-17. [PMID: 21474072 DOI: 10.1016/j.molcel.2011.02.021] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 12/10/2010] [Accepted: 01/20/2011] [Indexed: 01/10/2023]
Abstract
The majority of trypanosomal mitochondrial pre-mRNAs undergo massive uridine insertion/deletion editing, which creates open reading frames. Although the pre-editing addition of short 3' A tails is known to stabilize transcripts during and after the editing, the processing event committing the fully edited mRNAs to translation remained unknown. Here, we show that a heterodimer of pentatricopeptide repeat-containing (PPR) proteins, termed kinetoplast polyadenylation/uridylation factors (KPAFs) 1 and 2, induces the postediting addition of A/U heteropolymers by KPAP1 poly(A) polymerase and RET1 terminal uridyltransferase. Edited transcripts bearing 200- to 300-nucleotide-long A/U tails, but not short A tails, were enriched in translating ribosomal complexes and affinity-purified ribosomal particles. KPAF1 repression led to a selective loss of A/U-tailed mRNAs and concomitant inhibition of protein synthesis. These results establish A/U extensions as the defining cis-elements of translation-competent mRNAs. Furthermore, we demonstrate that A/U-tailed mRNA preferentially interacts with the small ribosomal subunit, whereas edited substrates and complexes bind to the large subunit.
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Affiliation(s)
- Inna Aphasizheva
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, Irvine, CA 92697, USA
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60
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Three mitochondrial DNA polymerases are essential for kinetoplast DNA replication and survival of bloodstream form Trypanosoma brucei. EUKARYOTIC CELL 2011; 10:734-43. [PMID: 21531873 DOI: 10.1128/ec.05008-11] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Trypanosoma brucei, the causative agent of human African trypanosomiasis, has a complex life cycle that includes multiple life cycle stages and metabolic changes as the parasite switches between insect vector and mammalian host. The parasite's single mitochondrion contains a unique catenated mitochondrial DNA network called kinetoplast DNA (kDNA) that is composed of minicircles and maxicircles. Long-standing uncertainty about the requirement of kDNA in bloodstream form (BF) T. brucei has recently eroded, with reports of posttranscriptional editing and subsequent translation of kDNA-encoded transcripts as essential processes for BF parasites. These studies suggest that kDNA and its faithful replication are indispensable for this life cycle stage. Here we demonstrate that three kDNA replication proteins (mitochondrial DNA polymerases IB, IC, and ID) are required for BF parasite viability. Silencing of each polymerase was lethal, resulting in kDNA loss, persistence of prereplication DNA monomers, and collapse of the mitochondrial membrane potential. These data demonstrate that kDNA replication is indeed crucial for BF T. brucei. The contributions of mitochondrial DNA polymerases IB, IC, and ID to BF parasite viability suggest that these and other kDNA replication proteins warrant further investigation as a new class of targets for the development of antitrypanosomal drugs.
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61
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Pereira CA, Bouvier LA, Cámara MDLM, Miranda MR. Singular features of trypanosomatids' phosphotransferases involved in cell energy management. Enzyme Res 2011; 2011:576483. [PMID: 21603267 PMCID: PMC3092577 DOI: 10.4061/2011/576483] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 01/23/2011] [Accepted: 02/08/2011] [Indexed: 01/15/2023] Open
Abstract
Trypanosomatids are responsible for economically important veterinary affections and severe human diseases. In Africa, Trypanosoma brucei causes sleeping sickness or African trypanosomiasis, while in America, Trypanosoma cruzi is the etiological agent of Chagas disease. These parasites have complex life cycles which involve a wide variety of environments with very different compositions, physicochemical properties, and availability of metabolites. As the environment changes there is a need to maintain the nucleoside homeostasis, requiring a quick and regulated response. Most of the enzymes required for energy management are phosphotransferases. These enzymes present a nitrogenous group or a phosphate as acceptors, and the most clear examples are arginine kinase, nucleoside diphosphate kinase, and adenylate kinase. Trypanosoma and Leishmania have the largest number of phosphotransferase isoforms ever found in a single cell; some of them are absent in mammals, suggesting that these enzymes are required in many cellular compartments associated to different biological processes. The presence of such number of phosphotransferases support the hypothesis of the existence of an intracellular enzymatic phosphotransfer network that communicates the spatially separated intracellular ATP consumption and production processes. All these unique features make phosphotransferases a promising start point for rational drug design for the treatment of human trypanosomiasis.
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Affiliation(s)
- Claudio A Pereira
- Laboratorio de Biología Molecular de Trypanosoma cruzi (LBMTC), Instituto de Investigaciones Médicas "Alfredo Lanari", Universidad de Buenos Aires and CONICET, Combatientes de Malvinas 3150, 1427 Buenos Aires, Argentina
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Paris Z, Hashimi H, Lun S, Alfonzo JD, Lukeš J. Futile import of tRNAs and proteins into the mitochondrion of Trypanosoma brucei evansi. Mol Biochem Parasitol 2011; 176:116-20. [PMID: 21195112 PMCID: PMC3042029 DOI: 10.1016/j.molbiopara.2010.12.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 12/17/2010] [Accepted: 12/22/2010] [Indexed: 11/30/2022]
Abstract
Trypanosoma brucei brucei has two distinct developmental stages, the procyclic stage in the insect and the bloodstream stage in the mammalian host. The significance of each developmental stage is punctuated by specific changes in metabolism. In the insect, T. b. brucei is strictly dependent on mitochondrial function and thus respiration to generate the bulk of its ATP, whereas in the mammalian host it relies heavily on glycolysis. These observations have raised questions about the importance of mitochondrial function in the bloodstream stage. Peculiarly, akinetoplastic strains of Trypanosoma brucei evansi that lack mitochondrial DNA do exist in the wild and are developmentally locked in the glycolysis-dependent bloodstream stage. Using RNAi we show that two mitochondrion-imported proteins, mitochondrial RNA polymerase and guide RNA associated protein 1, are still imported into the nucleic acids-lacking organelle of T. b. evansi, making the need for these proteins futile. We also show that, like in the T. b. brucei procyclic stage, the mitochondria of both bloodstream stage of T. b. brucei and T. b. evansi import various tRNAs, including those that undergo thiolation. However, we were unable to detect mitochondrial thiolation in the akinetoplastic organelle. Taken together, these data suggest a lack of connection between nuclear and mitochondrial communication in strains of T. b. evansi that lost mitochondrial genome and that do not required an insect vector for survival.
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Affiliation(s)
- Zdenĕk Paris
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, 37005, České Budějovice (Budweis), Czech Republic
| | - Hassan Hashimi
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, 37005, České Budějovice (Budweis), Czech Republic
- Faculty of Science, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic
| | - Sijia Lun
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, 37005, České Budějovice (Budweis), Czech Republic
| | - Juan D. Alfonzo
- Department of Microbiology and OSU Center for RNA Biology, The Ohio State University, Columbus, 43210 Ohio, USA
| | - Julius Lukeš
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, 37005, České Budějovice (Budweis), Czech Republic
- Faculty of Science, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic
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63
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Alfonzo JD, Lukeš J. Assembling Fe/S-clusters and modifying tRNAs: ancient co-factors meet ancient adaptors. Trends Parasitol 2011; 27:235-8. [PMID: 21419700 DOI: 10.1016/j.pt.2011.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 02/16/2011] [Accepted: 02/16/2011] [Indexed: 11/19/2022]
Abstract
Trypanosoma brucei undergoes two clearly distinct develomental stages: in the insect vector (procyclic stage) the cells generate the bulk of their energy through respiration, whereas in the bloodstream of the mammalian host (bloodstream stage) they grow mostly glycolytically. Several mitochondrial respiratory proteins require iron-sulfur clusters for activity, and their activation coincides with developmental changes. Likewise some tRNA modification enzymes either require iron-sulfur clusters or use components of the iron-sulfur cluster assembly pathway for activity. These enzymes affect the anticodon loop of various tRNAs and can impact protein synthesis. Herein, the possibility of these pathways being integrated and exploited by T. brucei to carefully coordinate energy demands to translational rates in response to enviromental changes is examined.
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Affiliation(s)
- Juan D Alfonzo
- Department of Microbiology and OSU Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA.
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Menna-Barreto RF, Beghini DG, Ferreira AT, Pinto AV, De Castro SL, Perales J. A proteomic analysis of the mechanism of action of naphthoimidazoles in Trypanosoma cruzi epimastigotes in vitro. J Proteomics 2010; 73:2306-15. [DOI: 10.1016/j.jprot.2010.07.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 06/28/2010] [Accepted: 07/02/2010] [Indexed: 11/30/2022]
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Evolution of bacterial phosphoglycerate mutases: non-homologous isofunctional enzymes undergoing gene losses, gains and lateral transfers. PLoS One 2010; 5:e13576. [PMID: 21187861 PMCID: PMC2964296 DOI: 10.1371/journal.pone.0013576] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Accepted: 09/27/2010] [Indexed: 11/28/2022] Open
Abstract
Background The glycolytic phosphoglycerate mutases exist as non-homologous isofunctional enzymes (NISE) having independent evolutionary origins and no similarity in primary sequence, 3D structure, or catalytic mechanism. Cofactor-dependent PGM (dPGM) requires 2,3-bisphosphoglycerate for activity; cofactor-independent PGM (iPGM) does not. The PGM profile of any given bacterium is unpredictable and some organisms such as Escherichia coli encode both forms. Methods/Principal Findings To examine the distribution of PGM NISE throughout the Bacteria, and gain insight into the evolutionary processes that shape their phyletic profiles, we searched bacterial genome sequences for the presence of dPGM and iPGM. Both forms exhibited patchy distributions throughout the bacterial domain. Species within the same genus, or even strains of the same species, frequently differ in their PGM repertoire. The distribution is further complicated by the common occurrence of dPGM paralogs, while iPGM paralogs are rare. Larger genomes are more likely to accommodate PGM paralogs or both NISE forms. Lateral gene transfers have shaped the PGM profiles with intradomain and interdomain transfers apparent. Archaeal-type iPGM was identified in many bacteria, often as the sole PGM. To address the function of PGM NISE in an organism encoding both forms, we analyzed recombinant enzymes from E. coli. Both NISE were active mutases, but the specific activity of dPGM greatly exceeded that of iPGM, which showed highest activity in the presence of manganese. We created PGM null mutants in E. coli and discovered the ΔdPGM mutant grew slowly due to a delay in exiting stationary phase. Overexpression of dPGM or iPGM overcame this defect. Conclusions/Significance Our biochemical and genetic analyses in E. coli firmly establish dPGM and iPGM as NISE. Metabolic redundancy is indicated since only larger genomes encode both forms. Non-orthologous gene displacement can fully account for the non-uniform PGM distribution we report across the bacterial domain.
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Týč J, Long S, Jirků M, Lukeš J. YCF45 protein, usually associated with plastids, is targeted into the mitochondrion of Trypanosoma brucei. Mol Biochem Parasitol 2010; 173:43-7. [DOI: 10.1016/j.molbiopara.2010.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 04/30/2010] [Accepted: 05/05/2010] [Indexed: 10/19/2022]
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Barata L, Sousa Silva M, Schuldt L, da Costa G, Tomás AM, Ferreira AEN, Weiss MS, Ponces Freire A, Cordeiro C. Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of glyoxalase I from Leishmania infantum. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:571-4. [PMID: 20445262 DOI: 10.1107/s1744309110010754] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Accepted: 03/22/2010] [Indexed: 05/26/2023]
Abstract
Glyoxalase I (GLO1) is the first of the two glyoxalase-pathway enzymes. It catalyzes the formation of S-D-lactoyltrypanothione from the non-enzymatically formed hemithioacetal of methylglyoxal and reduced trypanothione. In order to understand its substrate binding and catalytic mechanism, GLO1 from Leishmania infantum was cloned, overexpressed in Escherichia coli, purified and crystallized. Two crystal forms were obtained: a cube-shaped form and a rod-shaped form. While the cube-shaped form did not diffract X-rays at all, the rod-shaped form exhibited diffraction to about 2.0 A resolution. The crystals belonged to space group P2(1)2(1)2, with unit-cell parameters a = 130.03, b = 148.51, c = 50.63 A and three dimers of the enzyme per asymmetric unit.
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Affiliation(s)
- Lídia Barata
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Campo Grande, Edificio C8, 1149-016 Lisboa, Portugal
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68
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Ginger ML, McFadden GI, Michels PAM. Rewiring and regulation of cross-compartmentalized metabolism in protists. Philos Trans R Soc Lond B Biol Sci 2010; 365:831-45. [PMID: 20124348 DOI: 10.1098/rstb.2009.0259] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Plastid acquisition, endosymbiotic associations, lateral gene transfer, organelle degeneracy or even organelle loss influence metabolic capabilities in many different protists. Thus, metabolic diversity is sculpted through the gain of new metabolic functions and moderation or loss of pathways that are often essential in the majority of eukaryotes. What is perhaps less apparent to the casual observer is that the sub-compartmentalization of ubiquitous pathways has been repeatedly remodelled during eukaryotic evolution, and the textbook pictures of intermediary metabolism established for animals, yeast and plants are not conserved in many protists. Moreover, metabolic remodelling can strongly influence the regulatory mechanisms that control carbon flux through the major metabolic pathways. Here, we provide an overview of how core metabolism has been reorganized in various unicellular eukaryotes, focusing in particular on one near universal catabolic pathway (glycolysis) and one ancient anabolic pathway (isoprenoid biosynthesis). For the example of isoprenoid biosynthesis, the compartmentalization of this process in protists often appears to have been influenced by plastid acquisition and loss, whereas for glycolysis several unexpected modes of compartmentalization have emerged. Significantly, the example of trypanosomatid glycolysis illustrates nicely how mathematical modelling and systems biology can be used to uncover or understand novel modes of pathway regulation.
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Affiliation(s)
- Michael L Ginger
- Division of Biomedical and Life Sciences, School of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK.
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69
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Lipid metabolism in Trypanosoma brucei. Mol Biochem Parasitol 2010; 172:66-79. [PMID: 20382188 DOI: 10.1016/j.molbiopara.2010.04.001] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 03/31/2010] [Accepted: 04/01/2010] [Indexed: 11/28/2022]
Abstract
Trypanosoma brucei membranes consist of all major eukaryotic glycerophospholipid and sphingolipid classes. These are de novo synthesized from precursors obtained either from the host or from catabolised endocytosed lipids. In recent years, substantial progress has been made in the molecular and biochemical characterisation of several of these lipid biosynthetic pathways, using gene knockout or RNA interference strategies or by enzymatic characterization of individual reactions. Together with the completed genome, these studies have highlighted several possible differences between mammalian and trypanosome lipid biosynthesis that could be exploited for the development of drugs against the diseases caused by these parasites.
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70
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Balogun EO, Inaoka DK, Kido Y, Shiba T, Nara T, Aoki T, Honma T, Tanaka A, Inoue M, Matsuoka S, Michels PAM, Harada S, Kita K. Overproduction, purification, crystallization and preliminary X-ray diffraction analysis of Trypanosoma brucei gambiense glycerol kinase. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:304-8. [PMID: 20208167 PMCID: PMC2833043 DOI: 10.1107/s1744309110000369] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Accepted: 01/05/2010] [Indexed: 11/10/2022]
Abstract
In the bloodstream forms of human trypanosomes, glycerol kinase (GK; EC 2.7.1.30) is one of the nine glycosomally compartmentalized enzymes that are essential for energy metabolism. In this study, a recombinant Trypanosoma brucei gambiense GK (rTbgGK) with an N-terminal cleavable His(6) tag was overexpressed, purified to homogeneity and crystallized by the sitting-drop vapour-diffusion method using PEG 400 as a precipitant. A complete X-ray diffraction data set to 2.75 A resolution indicated that the crystals belonged to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 63.84, b = 121.50, c = 154.59 A. The presence of two rTbgGK molecules in the asymmetric unit gives a Matthews coefficient (V(M)) of 2.5 A(3) Da(-1), corresponding to 50% solvent content.
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Affiliation(s)
- Emmanuel Oluwadare Balogun
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Department of Biochemistry, Ahmadu Bello University, Zaria, Nigeria
| | - Daniel Ken Inaoka
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yasutoshi Kido
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Tomoo Shiba
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Takeshi Nara
- Department of Molecular and Cellular Parasitology, Juntendo University School of Medicine, Tokyo 113-8421, Japan
| | - Takashi Aoki
- Department of Molecular and Cellular Parasitology, Juntendo University School of Medicine, Tokyo 113-8421, Japan
| | - Teruki Honma
- Systems and Structural Biology Center, RIKEN, Tsurumi, Yokohama 230-0045, Japan
| | - Akiko Tanaka
- Systems and Structural Biology Center, RIKEN, Tsurumi, Yokohama 230-0045, Japan
| | - Masayuki Inoue
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Shigeru Matsuoka
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Paul A. M. Michels
- Research Unit for Tropical Diseases, de Duve Institute and Laboratory of Biochemistry, Université Catholique de Louvain, Avenue Hippocrate 74, B-1200 Brussels, Belgium
| | - Shigeharu Harada
- Department of Applied Biology, Graduate School of Science and Technology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585, Japan
| | - Kiyoshi Kita
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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71
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The assembly of F1FO-ATP synthase is disrupted upon interference of RNA editing in Trypanosoma brucei. Int J Parasitol 2010; 40:45-54. [DOI: 10.1016/j.ijpara.2009.07.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Revised: 06/18/2009] [Accepted: 07/07/2009] [Indexed: 11/20/2022]
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72
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Korený L, Lukes J, Oborník M. Evolution of the haem synthetic pathway in kinetoplastid flagellates: an essential pathway that is not essential after all? Int J Parasitol 2009; 40:149-56. [PMID: 19968994 DOI: 10.1016/j.ijpara.2009.11.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 11/27/2009] [Accepted: 11/28/2009] [Indexed: 01/10/2023]
Abstract
For a vast majority of living organisms, haem is an essential compound that is synthesised through a conserved biosynthetic pathway. However, certain organisms are haem auxotrophs and need to obtain this molecule from exogenous sources. Kinetoplastid flagellates represent an interesting group of species, as some of them lost the complete pathway while others possess only the last three biosynthetic steps. We decided to supplement a current view on the phylogeny of these important pathogens with the expected state of haem synthesis in representative species. We propose a scenario in which the ancestor of all trypanosomatids was completely deficient of the synthesis of haem. In trypanosomatids other than members of the genus Trypanosoma, the pathway was partially rescued by genes encoding enzymes for the last three steps, supposedly obtained by horizontal transfer from a gamma-proteobacterium. This event preceded the diversification of the non-Trypanosoma trypanosomatids. Later, some flagellates acquired a beta-proteobacterial endosymbiont which supplied them with haem precursors. On the other hand, the medically important trypanosomes have remained fully deficient of haem synthesis and obtain this compound from the host.
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Affiliation(s)
- Ludek Korený
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences and Faculty of Science, University of South Bohemia, Ceské Budejovice, Czech Republic
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73
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Nowicki MW, Kuaprasert B, McNae IW, Morgan HP, Harding MM, Michels PAM, Fothergill-Gilmore LA, Walkinshaw MD. Crystal structures of Leishmania mexicana phosphoglycerate mutase suggest a one-metal mechanism and a new enzyme subclass. J Mol Biol 2009; 394:535-43. [PMID: 19781556 DOI: 10.1016/j.jmb.2009.09.041] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 09/11/2009] [Accepted: 09/16/2009] [Indexed: 01/23/2023]
Abstract
The structures of Leishmania mexicana cofactor-independent phosphoglycerate mutase (Lm iPGAM) crystallised with the substrate 3-phosphoglycerate at high and low cobalt concentrations have been solved at 2.00- and 1.90-A resolutions. Both structures are very similar and the active site contains both 3-phosphoglycerate and 2-phosphoglycerate at equal occupancies (50%). Lm iPGAM co-crystallised with the product 2-phosphoglycerate yields the same structure. Two Co(2+) are coordinated within the active site with different geometries and affinities. The cobalt at the M1 site has a distorted octahedral geometry and is present at 100% occupancy. The M2-site Co(2+) binds with distorted tetrahedral geometry, with only partial occupancy, and coordinates with Ser75, the residue involved in phosphotransfer. When the M2 site is occupied, the side chain of Ser75 adopts a position that is unfavourable for catalysis, indicating that this site may not be occupied under physiological conditions and that catalysis may occur via a one-metal mechanism. The geometry of the M2 site suggests that it is possible for Ser75 to be activated for phosphotransfer by H-bonding to nearby residues rather than by metal coordination. The 16 active-site residues of Lm iPGAM are conserved in the Mn-dependent iPGAM from Bacillus stearothermophilus (33% overall sequence identity). However, Lm iPGAM has an inserted tyrosine (Tyr210) that causes the M2 site to diminish in size, consistent with its reduced metal affinity. Tyr210 is present in trypanosomatid and plant iPGAMs, but not in the enzymes from other organisms, indicating that there are two subclasses of iPGAMs.
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Affiliation(s)
- Matthew W Nowicki
- Structural Biochemistry Group, Institute of Structural and Molecular Biology, University of Edinburgh, King's Buildings, Edinburgh, UK
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74
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Tielens AGM, van Hellemond JJ. Surprising variety in energy metabolism within Trypanosomatidae. Trends Parasitol 2009; 25:482-90. [PMID: 19748317 DOI: 10.1016/j.pt.2009.07.007] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Revised: 07/02/2009] [Accepted: 07/14/2009] [Indexed: 11/19/2022]
Abstract
The metabolism of Trypanosomatidae differs significantly between distinct species and can even be completely different between various life-cycle stages of the same species. It has been proposed that differences in energy metabolism are related to differences in nutrient supply in the environments of the various trypanosomatids. However, the literature shows that availability of substrates does not dictate the type of energy metabolism of trypanosomatids, as Trypanosoma theileri, Trypanosoma lewisi and African trypanosomes all live in the bloodstream of their mammalian host, but have surprisingly large differences in metabolism. Furthermore, in trypanosomatids no obvious relationship exists between energy metabolism and phylogeny or mode of transmission. We provide an overview of the metabolic capacities in the energy metabolism of distinct trypanosomatids, and suggest that these can be divided into four different metabolic categories of increasing complexity.
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Affiliation(s)
- Aloysius G M Tielens
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, University Medical Centre Rotterdam, 'S Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.
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75
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Functional characterization of stage-specific aminotransferases from trypanosomatids. Mol Biochem Parasitol 2009; 166:172-82. [DOI: 10.1016/j.molbiopara.2009.04.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Revised: 03/20/2009] [Accepted: 04/02/2009] [Indexed: 11/19/2022]
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76
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Adaptations in the glucose metabolism of procyclic Trypanosoma brucei isolates from tsetse flies and during differentiation of bloodstream forms. EUKARYOTIC CELL 2009; 8:1307-11. [PMID: 19542311 DOI: 10.1128/ec.00091-09] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Procyclic forms of Trypanosoma brucei isolated from the midguts of infected tsetse flies, or freshly transformed from a strain that is close to field isolates, do not use a complete Krebs cycle. Furthermore, short stumpy bloodstream forms produce acetate and are apparently metabolically preadapted to adequate functioning in the tsetse fly.
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77
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Marín C, Boutaleb-Charki S, Díaz JG, Huertas O, Rosales MJ, Pérez-Cordon G, Guitierrez-Sánchez R, Sánchez-Moreno M. Antileishmaniasis activity of flavonoids from Consolida oliveriana. JOURNAL OF NATURAL PRODUCTS 2009; 72:1069-1074. [PMID: 19489596 DOI: 10.1021/np8008122] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A set of flavonoids from Consolida oliveriana, kaempferol (1), quercetin (2), trifolin (3), and acetyl hyperoside (5) and their O-acetyl derivatives (1a, 2a, 3a), and octa-O-acetylhyperoside (4) showed leishmanicidal activity against promastigote as well as amastigote forms of Leishmania spp. The cellular proliferation, metabolic, and ultrastructural studies showed that the acetylated compounds 2a, 3a, and 4 were highly active against Leishmania (V.) peruviana, while 2a as well as 4 were effective against Leishmania (V.) braziliensis. These compounds were not cytotoxic and are effective at similar concentrations up to or lower than the reference drugs (pentostam and glucantim).
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Affiliation(s)
- Clotilde Marín
- Department of Parasitology, University of Granada, Granada, Spain
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78
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Identification, characterization and essentiality of the unusual peroxin 13 from Trypanosoma brucei. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2009; 1793:516-27. [PMID: 19185591 DOI: 10.1016/j.bbamcr.2008.12.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Revised: 12/08/2008] [Accepted: 12/18/2008] [Indexed: 11/20/2022]
Abstract
Peroxin 13 (PEX13) is one of the components of a peroxisomal membrane complex involved in import of proteins into the matrix of the organelles and has previously been characterized in a variety of organisms. Trypanosomatids (Trypanosoma, Leishmania), protozoan parasites having peroxisome-like organelles designated glycosomes, possess an unusual PEX13 which shares very low sequence identity with others and lacks some typical PEX13 characteristics. It was identified in the databases through its multiple YGx motifs present in a glycine-rich N-terminal region of low sequence complexity. Like other PEX13s, it contains predicted transmembrane segments and a SH3 domain in its C-terminal half. The localization of T. brucei PEX13 in the glycosomal membrane was confirmed by expression of a fusion construct with Green Fluorescent Protein, and western blot analysis of purified organelles and membranes. The C-terminal half of the protein was shown to interact with the third of three pentapeptide repeats of the previously characterized PEX5, the receptor of glycosomal proteins with a type 1 peroxisome-targeting signal, and with PEX14, another component of the same peroxisomal protein import complex in the membrane. PEX13 is essential for the parasite; depletion by RNA interference results in mislocalization of glycosomal proteins and death of the parasites.
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79
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Nebohácová M, Kim CE, Simpson L, Maslov DA. RNA editing and mitochondrial activity in promastigotes and amastigotes of Leishmania donovani. Int J Parasitol 2008; 39:635-44. [PMID: 19109964 DOI: 10.1016/j.ijpara.2008.10.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Revised: 10/29/2008] [Accepted: 10/30/2008] [Indexed: 11/30/2022]
Abstract
Kinetoplast maxicircle DNA sequence organisation was investigated in Leishmania donovani, strain 1S LdBob. Gene arrangement in the coding (conserved) region of the maxicircle is collinear with that of most trypanosomatids, with individual genes showing 80-90% nucleotide identity to Leishmania tarentolae, strain UC. The notable exception was an integration of a full-size minicircle sequence in the ND1 gene coding region found in L. donovani. Editing patterns of the mitochondrial mRNAs investigated also followed L. tarentolae UC patterns, including productive editing of the components of respiratory complexes III-V, and ribosomal protein S12 (RPS12), as well as the lack of productive editing in five out of six pan-edited cryptogenes (ND3, ND8, ND9, G3, G4) found in these species. Several guide RNAs for the editing events were localised in minicircles and maxicircles in the locations that are conserved between the species. Mitochondrial activity, including rates of oxygen consumption, the presence and the levels of respiratory complexes and their individual subunits and the steady-state levels of several mitochondrial-encoded mRNAs were essentially the same in axenically grown amastigotes and in promastigotes of L. donovani. However, some modulation of mitochondrial activity between these developmental stages was suggested by the finding of an amastigote-specific component in complex IV, a down-regulation of mitochondrial RNA-binding proteins (MRP) and MRP-associated protein (MRP-AP) in amastigotes, and by variations in the levels of RPS12, ND3, ND9, G3 and G4 pre-edited transcripts.
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Affiliation(s)
- Martina Nebohácová
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
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80
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Deschamps P, Haferkamp I, d'Hulst C, Neuhaus HE, Ball SG. The relocation of starch metabolism to chloroplasts: when, why and how. TRENDS IN PLANT SCIENCE 2008; 13:574-82. [PMID: 18824400 DOI: 10.1016/j.tplants.2008.08.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2008] [Revised: 08/13/2008] [Accepted: 08/14/2008] [Indexed: 05/18/2023]
Abstract
Plastid endosymbiosis was accompanied by the appearance of a novel type of semi-cristalline storage polysaccharide (starch). Interestingly, starch is found in the cytoplasm of Rhodophyceae and Glaucophyta but is localized to the chloroplast stroma of Chloroplastida. The pathway is presumed to have been cytosolic in the common ancestor of the three Archaeplastida lineages. The means by which in green plants and algae an entire suite of nuclear-encoded starch-metabolism genes could have had their protein products rewired simultaneously to plastids are unclear. This opinion article reviews the timing and the possible reasons underlying this rewiring and proposes a hypothesis that explains its mechanism. The consequences of this mechanism on the complexity of starch metabolism in Chloroplastida are discussed.
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Affiliation(s)
- Philippe Deschamps
- Laboratoire de Chimie Biologique, Université des Sciences et technologies de Lille, CNRS, UMR8576, Cité Scientifique, Villeneuve d'Ascq, France
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81
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The KREPA3 zinc finger motifs and OB-fold domain are essential for RNA editing and survival of Trypanosoma brucei. Mol Cell Biol 2008; 28:6939-53. [PMID: 18794366 DOI: 10.1128/mcb.01115-08] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Three types of editosomes, each with an identical core containing six related KREPA proteins, catalyze the U insertion and deletion RNA editing of mitochondrial mRNAs in trypanosomes. Repression of expression of one of these, KREPA3 (also known as TbMP42), shows that it is essential for growth and in vivo editing in both procyclic (PF) and bloodstream (BF) life cycle stages of Trypanosoma brucei. RNA interference knockdown results in editosome disruption and altered in vitro editing in PFs, while repression by regulatable double knockout results in almost complete loss of editosomes in BFs. Mutational analysis shows that the KREPA3 zinc fingers and OB-fold domain are each essential for growth and in vivo editing. Nevertheless, KREPA3 with mutated zinc fingers incorporates into editosomes that catalyze in vitro editing and thus is not essential for editosome integrity, although stability is affected. In contrast, the OB-fold domain is essential for editosome integrity. Overall, KREPA3, especially its OB-fold, functions in editosome integrity, and its zinc fingers are essential for editing in vivo but not for the central catalytic steps. KREPA3 may function in editosome organization and/or RNA positioning.
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82
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The Leishmania HSP20 is antigenic during natural infections, but, as DNA vaccine, it does not protect BALB/c mice against experimental L. amazonensis infection. J Biomed Biotechnol 2008; 2008:695432. [PMID: 18401455 PMCID: PMC2288687 DOI: 10.1155/2008/695432] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 01/08/2008] [Accepted: 02/21/2008] [Indexed: 11/22/2022] Open
Abstract
Protozoa of the genus Leishmania are causative agents
of leishmaniasis, an important health problem in both human and veterinary medicine. Here,
we describe a new heat shock protein (HSP) in Leishmania, belonging to
the small HSP (sHSP) family in kinetoplastids. The protein is highly conserved in
different Leishmania species, showing instead significant divergence
with sHSP's from other organisms. The humoral response elicited against this protein
during Leishmania infection has been investigated in natural infected
humans and dogs, and in experimentally infected hamsters. Leishmania
HSP20 is a prominent antigen for canine hosts; on the contrary, the protein seems to
be a poor antigen for human immune system. Time-course analysis of appearance of
anti-HSP20 antibodies in golden hamsters indicated that these antibodies are produced
at late stages of the infection, when clinical symptoms of disease are patent. Finally, the
protective efficacy of HSP20 was assessed in mice using a DNA vaccine approach prior to
challenge with Leishmania amazonensis.
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83
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Igoillo-Esteve M, Maugeri D, Stern AL, Beluardi P, Cazzulo JJ. The pentose phosphate pathway in Trypanosoma cruzi: a potential target for the chemotherapy of Chagas disease. AN ACAD BRAS CIENC 2008; 79:649-63. [PMID: 18066434 DOI: 10.1590/s0001-37652007000400007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Accepted: 08/17/2007] [Indexed: 11/21/2022] Open
Abstract
Trypanosoma cruzi is highly sensitive to oxidative stress caused by reactive oxygen species. Trypanothione, the parasite's major protection against oxidative stress, is kept reduced by trypanothione reductase, using NADPH; the major source of the reduced coenzyme seems to be the pentose phosphate pathway. Its seven enzymes are present in the four major stages in the parasite's biological cycle; we have cloned and expressed them in Escherichia coli as active proteins. Glucose 6-phosphate dehydrogenase, which controls glucose flux through the pathway by its response to the NADP/NADPH ratio, is encoded by a number of genes per haploid genome, and is induced up to 46-fold by hydrogen peroxide in metacyclic trypomastigotes. The genes encoding 6-phosphogluconolactonase, 6-phosphogluconate dehydrogenase, transaldolase and transketolase are present in the CL Brener clone as a single copy per haploid genome. 6-phosphogluconate dehydrogenase is very unstable, but was stabilized introducing two salt bridges by site-directed mutagenesis. Ribose-5-phosphate isomerase belongs to Type B; genes encoding Type A enzymes, present in mammals, are absent. Ribulose-5-phosphate epimerase is encoded by two genes. The enzymes of the pathway have a major cytosolic component, although several of them have a secondary glycosomal localization, and also minor localizations in other organelles.
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Affiliation(s)
- Mariana Igoillo-Esteve
- Instituto de Investigaciones Biotecnologicas, Instituto Tecnologico de Chascomus, Provincia de Buenos Aires, Argentina
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84
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Zeiman E, Greenblatt CL, Elgavish S, Khozin-Goldberg I, Golenser J. Mode of action of fenarimol against Leishmania spp. J Parasitol 2008; 94:280-6. [PMID: 18372651 DOI: 10.1645/ge-1259.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
This paper evaluates the effects of certain herbicides on Leishmania spp., their mechanism of action, and the evolutionary origin of the relevant susceptible leishmanial targets. We demonstrated that a relatively nontoxic herbicide, fenarimol, successfully interferes with a leishmanial target, which is probably a relic of an ancient ancestor. Fenarimol impairs the function of leishmanial 14alpha-sterol demethylase, a key enzyme in the sterol biosynthetic pathway. Therefore, fenarimol or its derivatives may be candidates for development of anti-leishmanial drugs. Of the herbicides that have the capability to act as potential inhibitors of the metabolism of Leishmania spp., fenarimol was found as the most active substance against both promastigotes and amastigotes in culture. In addition, it ameliorated lesions caused by Leishmania major in mice. Light microscopy demonstrated rounding of the parasite shape. Increase of osmophilic vacuoles and autophagosomal structures were observed by transmission electron microscopy. Biochemical studies demonstrated that fenarimol inhibited sterol biosynthesis. Docking of fenarimol to the modeled catalytic binding site of 14alpha-lanosterol demethylase of L. major showed a geometrical fit. Fenarimol is stabilized via hydrophobic interactions with the residues that surround it and interactions with the heme ring. These results provide support to the hypothesis that fenarimol inhibits leishmanial sterol biosynthesis. Overall, the findings suggest an additional source of substances for development of anti-leishmanial drugs.
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Affiliation(s)
- Einat Zeiman
- Department of Parasitology, The Hebrew University-Hadassah Medical School, Jerusalem, Israel 91120
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85
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Chavali AK, Whittemore JD, Eddy JA, Williams KT, Papin JA. Systems analysis of metabolism in the pathogenic trypanosomatid Leishmania major. Mol Syst Biol 2008; 4:177. [PMID: 18364711 PMCID: PMC2290936 DOI: 10.1038/msb.2008.15] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Accepted: 02/06/2008] [Indexed: 12/18/2022] Open
Abstract
Systems analyses have facilitated the characterization of metabolic networks of several organisms. We have reconstructed the metabolic network of Leishmania major, a poorly characterized organism that causes cutaneous leishmaniasis in mammalian hosts. This network reconstruction accounts for 560 genes, 1112 reactions, 1101 metabolites and 8 unique subcellular localizations. Using a systems-based approach, we hypothesized a comprehensive set of lethal single and double gene deletions, some of which were validated using published data with approximately 70% accuracy. Additionally, we generated hypothetical annotations to dozens of previously uncharacterized genes in the L. major genome and proposed a minimal medium for growth. We further demonstrated the utility of a network reconstruction with two proof-of-concept examples that yielded insight into robustness of the network in the presence of enzymatic inhibitors and delineation of promastigote/amastigote stage-specific metabolism. This reconstruction and the associated network analyses of L. major is the first of its kind for a protozoan. It can serve as a tool for clarifying discrepancies between data sources, generating hypotheses that can be experimentally validated and identifying ideal therapeutic targets.
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Affiliation(s)
- Arvind K Chavali
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Jeffrey D Whittemore
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - James A Eddy
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Kyle T Williams
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Jason A Papin
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
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86
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Luque-Ortega JR, van't Hof W, Veerman ECI, Saugar JM, Rivas L. Human antimicrobial peptide histatin 5 is a cell-penetrating peptide targeting mitochondrial ATP synthesis in Leishmania. FASEB J 2008; 22:1817-28. [PMID: 18230684 DOI: 10.1096/fj.07-096081] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Histatin 5 (Hst5) is a human salivary antimicrobial peptide that targets fungal mitochondria. In the human parasitic protozoa Leishmania, the mitochondrial ATP production is essential, as it lacks the bioenergetic switch between glycolysis and oxidative phosphorylation described in some yeasts. On these premises, Hst5 activity was assayed on both stages of its life cycle, promastigotes and amastigotes (LC(50)=7.3 and 14.4 microM, respectively). In a further step, its lethal mechanism was studied. The main conclusions drawn were as follows: 1) Hst5 causes limited and temporary damage to the plasma membrane of the parasites, as assessed by electron microscopy, depolarization, and entrance of the vital dye SYTOX Green; 2) Hst5 translocates into the cytoplasm of Leishmania in an achiral receptor-independent manner with accumulation into the mitochondrion, as shown by confocal microscopy; and 3) Hst5 produces a bioenergetic collapse of the parasite, caused essentially by the decrease of mitochondrial ATP synthesis through inhibition of F(1)F(0)-ATPase, with subsequent fast ATP exhaustion. By using the Hst5 enantiomer, it was found that the key steps of its lethal mechanism involved no chiral recognition. Hst5 thus constitutes the first leishmanicidal peptide with a defined nonstereospecific intracellular target. The prospects of its development, by its own or as a carrier molecule for other leishmanicidal molecules, into a novel anti-Leishmania drug with a preferential subcellular accumulation are discussed.
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87
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Morphological Discordance of the New Trypanosomatid Species Phylogenetically Associated with the Genus Crithidia. Protist 2008; 159:99-114. [DOI: 10.1016/j.protis.2007.07.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Accepted: 07/14/2007] [Indexed: 11/17/2022]
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88
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Sousa Silva M, Barata L, Ferreira AEN, Romão S, Tomás AM, Ponces Freire A, Cordeiro C. Catalysis and Structural Properties of Leishmania infantum Glyoxalase II: Trypanothione Specificity and Phylogeny,. Biochemistry 2007; 47:195-204. [DOI: 10.1021/bi700989m] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marta Sousa Silva
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Lisboa, and Institutos de Biologia Molecular e Celular (IBMC) and de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Lídia Barata
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Lisboa, and Institutos de Biologia Molecular e Celular (IBMC) and de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - António E. N. Ferreira
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Lisboa, and Institutos de Biologia Molecular e Celular (IBMC) and de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Susana Romão
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Lisboa, and Institutos de Biologia Molecular e Celular (IBMC) and de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Ana M. Tomás
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Lisboa, and Institutos de Biologia Molecular e Celular (IBMC) and de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Ana Ponces Freire
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Lisboa, and Institutos de Biologia Molecular e Celular (IBMC) and de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Carlos Cordeiro
- Centro de Química e Bioquímica, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Lisboa, Lisboa, and Institutos de Biologia Molecular e Celular (IBMC) and de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
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89
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St-Jean M, Sygusch J. Stereospecific Proton Transfer by a Mobile Catalyst in Mammalian Fructose-1,6-bisphosphate Aldolase. J Biol Chem 2007; 282:31028-37. [PMID: 17728250 DOI: 10.1074/jbc.m704968200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Class I fructose-1,6-bisphosphate aldolases catalyze the interconversion between the enamine and iminium covalent enzymatic intermediates by stereospecific exchange of the pro(S) proton of the dihydroxyacetone-phosphate C3 carbon, an obligatory reaction step during substrate cleavage. To investigate the mechanism of stereospecific proton exchange, high resolution crystal structures of native and a mutant Lys(146) --> Met aldolase were solved in complex with dihydroxyacetone phosphate. The structural analysis revealed trapping of the enamine intermediate at Lys(229) in native aldolase. Mutation of conserved active site residue Lys(146) to Met drastically decreased activity and enabled trapping of the putative iminium intermediate in the crystal structure showing active site attachment by C-terminal residues 360-363. Attachment positions the conserved C-terminal Tyr(363) hydroxyl within 2.9A of the C3 carbon in the iminium in an orientation consistent with incipient re face proton transfer. We propose a catalytic mechanism by which the mobile C-terminal Tyr(363) is activated by the iminium phosphate via a structurally conserved water molecule to yield a transient phenate, whose developing negative charge is stabilized by a Lys(146) positive charge, and which abstracts the C3 pro(S) proton forming the enamine. An identical C-terminal binding mode observed in the presence of phosphate in the native structure corroborates Tyr(363) interaction with Lys(146) and is consistent with transient C terminus binding in the enamine. The absence of charge stabilization and of a mobile C-terminal catalyst explains the extraordinary stability of enamine intermediates in transaldolases.
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Affiliation(s)
- Miguel St-Jean
- Department of Biochemistry, Université de Montréal, Montréal, Québec H3C 3J7, Canada
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90
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Lafrance-Vanasse J, Sygusch J. Carboxy-terminus recruitment induced by substrate binding in eukaryotic fructose bis-phosphate aldolases. Biochemistry 2007; 46:9533-40. [PMID: 17661446 DOI: 10.1021/bi700615r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The crystal structures of Leishmania mexicana fructose-1,6-bis(phosphate) aldolase in complex with substrate and competitive inhibitor, mannitol-1,6-bis(phosphate), were solved to 2.2 A resolution. Crystallographic analysis revealed a Schiff base intermediate trapped in the native structure complexed with substrate while the inhibitor was trapped in a conformation mimicking the carbinolamine intermediate. Binding modes corroborated previous structures reported for rabbit muscle aldolase. Amino acid substitution of Gly-312 to Ala, adjacent to the P1-phosphate binding site and unique to trypanosomatids, did not perturb ligand binding in the active site. Ligand attachment ordered amino acid residues 359-367 of the C-terminal region (353-373) that was disordered beyond Asp-358 in the unbound structure, revealing a novel recruitment mechanism of this region by aldolases. C-Terminal peptide ordering is triggered by P1-phosphate binding that induces conformational changes whereby C-terminal Leu-364 contacts P1-phosphate binding residue Arg-313. C-Terminal region capture synergizes additional interactions with subunit surface residues, not perturbed by P1-phosphate binding, and stabilizes C-terminal attachment. Amino acid residues that participate in the capturing interaction are conserved among class I aldolases, indicating a general recruitment mechanism whereby C-terminal capture facilitates active site interactions in subsequent catalytic steps. Recruitment accelerates the enzymatic reaction by using binding energy to reduce configurational entropy during catalysis thereby localizing the conserved C-terminus tyrosine, which mediates proton transfer, proximal to the active site enamine.
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91
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Raverdy S, Zhang Y, Foster J, Carlow CKS. Molecular and biochemical characterization of nematode cofactor independent phosphoglycerate mutases. Mol Biochem Parasitol 2007; 156:210-6. [PMID: 17897734 DOI: 10.1016/j.molbiopara.2007.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 08/10/2007] [Accepted: 08/13/2007] [Indexed: 11/20/2022]
Abstract
Phosphoglycerate mutase (PGM, EC 5.4.2.1) catalyzes the isomerization of 3-phosphoglycerate and 2-phosphoglycerate in glycolysis and gluconeogenesis. Two distinct types of PGM exist in nature, one that requires 2,3-bisphosphoglycerate as a cofactor (dPGM) and another that does not (iPGM). The two enzymes are structurally distinct and possess different mechanisms of action. In any particular organism, one form may exist or both. Nematodes possess the iPGM form whereas mammals have dPGM. In the present study, we have cloned and expressed iPGM from Onchocerca volvulus and described the catalytic properties of O. volvulus, Brugia malayi and Caenorhabditis elegans iPGM enzymes. Temperature and pH optima were determined for each enzyme. Like other iPGM enzymes, the activities of the nematode iPGM enzymes were dependent on the presence of divalent ions. Inactivation by EDTA could be restored most effectively by magnesium and manganese ions. Kinetic parameters and specific activities of the various recombinant enzymes were determined. The high similarity in catalytic properties among the enzymes indicates that a single enzyme inhibitor would likely be effective against all nematode enzymes. Inhibition of iPGM activity in vivo may lead to lethality as indicated by RNAi studies in C. elegans. Our results support the development of iPGM as a promising drug target in parasitic nematodes.
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Affiliation(s)
- Sylvine Raverdy
- New England Biolabs, Division of Parasitology, 240 County Road, Ipswich, MA 01938, USA
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92
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van Hellemond JJ, Hoek A, Wichgers Schreur P, Chupin V, Ozdirekcan S, Geysen D, van Grinsven KWA, Koets AP, Van den Bossche P, Geerts S, Tielens AGM. Energy metabolism of bloodstream form Trypanosoma theileri. EUKARYOTIC CELL 2007; 6:1693-6. [PMID: 17644652 PMCID: PMC2043366 DOI: 10.1128/ec.00130-07] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Bloodstream form Trypanosoma theileri degrades glucose to acetate (47%) and succinate (45%) and, therefore, does not solely rely on glycolysis for ATP production. This trypanosomatid does not use amino acids for energy metabolism. These results refute the prevailing hypothesis that substrate availability determines the type of energy metabolism of trypanosomatids.
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Affiliation(s)
- Jaap J van Hellemond
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80176, 3508 TD Utrecht, The Netherlands
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93
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Fernandez P, Haouz A, Pereira CA, Aguilar C, Alzari PM. The crystal structure of Trypanosoma cruzi arginine kinase. Proteins 2007; 69:209-12. [PMID: 17623863 DOI: 10.1002/prot.21557] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Pablo Fernandez
- Unité de Biochimie Structurale, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris, France
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94
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Quiñones W, Peña P, Domingo-Sananes M, Cáceres A, Michels PAM, Avilan L, Concepción JL. Leishmania mexicana: Molecular cloning and characterization of enolase. Exp Parasitol 2007; 116:241-51. [PMID: 17382932 DOI: 10.1016/j.exppara.2007.01.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Revised: 12/23/2006] [Accepted: 01/11/2007] [Indexed: 10/23/2022]
Abstract
The gene of Leishmania mexicana enolase was cloned and overexpressed in Escherichia coli as an active enzyme; the protein was biochemically analyzed. This enolase shares with enolases from other trypanosomatids the presence of three atypical residues, each with a reactive side group, near the active site, already described for the enzyme from Trypanosoma brucei. The natural enzyme was purified, using a three-step procedure, from a cytosolic fraction of L. mexicana promastigotes. The kinetic properties of the purified recombinant enzyme were similar to those of the natural enzyme. Both the recombinant and natural enzyme were inhibited by inorganic pyrophosphate. Subcellular localization analysis after differential centrifugation showed that the enzyme activity is only associated with the cytosolic fraction. However, an apparently inactive form of enolase was detected by Western blots in the microsomal fraction. Digitonin treatment of parasites and immunofluorescence studies with permeabilized and non-permeabilized parasites showed that enolase is also associated with membranes and it was found at the external face of the plasma membrane.
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Affiliation(s)
- Wilfredo Quiñones
- Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de Los Andes, Apartado Postal 38, Ipostel-La hechicera, Mérida, Venezuela
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95
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Abstract
The kinetoplastids Leishmania major, Trypanosoma brucei and Trypanosoma cruzi are causative agents of a diverse spectrum of human diseases: leishmaniasis, sleeping sickness and Chagas' disease, respectively. These protozoa possess digenetic life cycles that involve development in mammalian and insect hosts. It is generally accepted that temperature is a triggering factor of the developmental programme allowing the adaptation of the parasite to the mammalian conditions. The heat shock response is a general homeostatic mechanism that protects cells from the deleterious effects of environmental stresses, such as heat. This response is universal and includes the synthesis of the heat-shock proteins (HSPs). In this review, we summarize the salient features of the different HSP families and describe their main cellular functions. In parallel, we analyse the composition of these families in kinetoplastids according to literature data and our understanding of genome sequence data. The genome sequences of these parasites have been recently completed. The HSP families described here are: HSP110, HSP104, group I chaperonins, HSP90, HSP70, HSP40 and small HSPs. All these families are widely represented in these parasites. In particular, kinetoplastids possess an unprecedented number of members of the HSP70, HSP60 and HSP40 families, suggesting key roles for these HSPs in their biology.
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Affiliation(s)
- Cristina Folgueira
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Madrid, Spain
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96
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Abstract
Ever since the elucidation of the main structural and functional features of eukaryotic cells and subsequent discovery of the endosymbiotic origin of mitochondria and plastids, two opposing hypotheses have been proposed to account for the origin of eukaryotic cells. One hypothesis postulates that the main features of these cells, including their ability to capture food by endocytosis and to digest it intracellularly, were developed first, and later had a key role in the adoption of endosymbionts; the other proposes that the transformation was triggered by an interaction between two typical prokaryotic cells, one of which became the host and the other the endosymbiont. Re-examination of this question in the light of cell-biological and phylogenetic data leads to the conclusion that the first model is more likely to be the correct one.
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Affiliation(s)
- Christian de Duve
- Christian de Duve Institute of Cellular Pathology (ICP), 75 Avenue Hippocrate, B-1200 Brussels, Belgium.
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97
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Comini MA, Krauth-Siegel RL, Flohé L. Depletion of the thioredoxin homologue tryparedoxin impairs antioxidative defence in African trypanosomes. Biochem J 2007; 402:43-9. [PMID: 17040206 PMCID: PMC1783994 DOI: 10.1042/bj20061341] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In trypanosomes, the thioredoxin-type protein TXN (tryparedoxin) is a multi-purpose oxidoreductase that is involved in the detoxification of hydroperoxides, the synthesis of DNA precursors and the replication of the kinetoplastid DNA. African trypanosomes possess two isoforms that are localized in the cytosol and in the mitochondrion of the parasites respectively. Here we report on the biological significance of the cTXN (cytosolic TXN) of Trypanosoma brucei for hydroperoxide detoxification. Depending on the growth phase, the concentration of the protein is 3-7-fold higher in the parasite form infecting mammals (50-100 microM) than in the form hosted by the tsetse fly (7-34 microM). Depletion of the mRNA in bloodstream trypanosomes by RNA interference revealed the indispensability of the protein. Proliferation and viability of cultured trypanosomes were impaired when TXN was lowered to 1 muM for more than 48 h. Although the levels of glutathione, glutathionylspermidine and trypanothione were increased 2-3.5-fold, the sensitivity against exogenously generated H2O2 was significantly enhanced. The results prove the essential role of the cTXN and its pivotal function in the parasite defence against oxidative stress.
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Affiliation(s)
- Marcelo A Comini
- Centre of Biochemistry, Heidelberg University, Im Neuenheimer Feld 504, D-69120, Heidelberg, Germany.
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98
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Opperdoes FR, Coombs GH. Metabolism of Leishmania: proven and predicted. Trends Parasitol 2007; 23:149-58. [PMID: 17320480 DOI: 10.1016/j.pt.2007.02.004] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2006] [Revised: 01/04/2007] [Accepted: 02/09/2007] [Indexed: 11/16/2022]
Abstract
The complete analysis of the genomes of three major trypanosomatid parasites has facilitated comparison of the metabolic capabilities of each, as predicted from gene sequences. Not surprisingly, there are differences but is it possible to correlate these with the lives of the parasites themselves and make further predictions of the meaning and physiological importance of the apparently parasite-specific metabolism? In this article, we relate gene predictions with the results from experimental studies. We also speculate on the key metabolic adaptations of Leishmania and reasons why it differs from Trypanosoma brucei and Trypanosoma cruzi.
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Affiliation(s)
- Fred R Opperdoes
- Research Unit for Tropical Diseases and Laboratory of Biochemistry, Christian de Duve Institute of Cellular Pathology and Catholic University of Louvain, Avenue Hippocrate 74-75, B-1200 Brussels, Belgium
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99
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Galland N, Demeure F, Hannaert V, Verplaetse E, Vertommen D, Van der Smissen P, Courtoy PJ, Michels PAM. Characterization of the role of the receptors PEX5 and PEX7 in the import of proteins into glycosomes of Trypanosoma brucei. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:521-35. [PMID: 17320990 DOI: 10.1016/j.bbamcr.2007.01.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 12/20/2006] [Accepted: 01/11/2007] [Indexed: 10/23/2022]
Abstract
Peroxins 5 and 7 are receptors for protein import into the peroxisomal matrix. We studied the involvement of these peroxins in the biogenesis of glycosomes in the protozoan parasite Trypanosoma brucei. Glycosomes are peroxisome-like organelles in which a major part of the glycolytic pathway is sequestered. We here report the characterization of the T. brucei homologue of PEX7 and provide several data strongly suggesting that it can bind to PEX5. Depletion of PEX5 or PEX7 by RNA interference had a severe effect on the growth of both the bloodstream-form of the parasite, that relies entirely on glycolysis for its ATP supply, and the procyclic form representative of the parasite living in the tsetse-fly midgut and in which also other metabolic pathways play a prominent role. The role of the two receptors in import of glycosomal matrix proteins with different types of peroxisome/glycosome-targeting signals (PTS) was analyzed by immunofluorescence and subcellular fractionation studies. Knocking down the expression of either receptor gene resulted, in procyclic cells, in the mislocalization of proteins with both a type 1 or 2 targeting motif (PTS1, PTS2) located at the C- and N-termini, respectively, and proteins with a sequence-internal signal (I-PTS) to the cytosol. Electron microscopy confirmed the apparent integrity of glycosomes in these procyclic cells. In bloodstream-form trypanosomes, PEX7 depletion seemed to affect only the subcellular distribution of PTS2-proteins. Western blot analysis suggested that, in both life-cycle stages of the trypanosome, the levels of both receptors are controlled in a coordinated fashion, by a mechanism that remains to be determined. The observation that both PEX5 and PEX7 are essential for the viability of the parasite indicates that the respective branches of the glycosome-import pathway in which each receptor acts might be interesting drug targets.
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Affiliation(s)
- Nathalie Galland
- Research Unit for Tropical Diseases, Christian de Duve Institute of Cellular Pathology and Laboratory of Biochemistry, Université catholique de Louvain, Brussels, Belgium
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100
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Pabón MA, Cáceres AJ, Gualdrón M, Quiñones W, Avilán L, Concepción JL. Purification and characterization of hexokinase from Leishmania mexicana. Parasitol Res 2006; 100:803-10. [PMID: 17061112 DOI: 10.1007/s00436-006-0351-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Accepted: 09/26/2006] [Indexed: 11/29/2022]
Abstract
Hexokinase from Leishmania mexicana was purified to homogeneity from a glycosome-enriched fraction obtained after a differential centrifugation of promastigote form. The kinetic properties of the pure enzyme were determined and the Km values for glucose (Km = 66 microM) and ATP (Km = 303 muM) were comparable to those from hexokinase of Trypanosoma cruzi. L. mexicana hexokinase was able to use fructose (Km = 142 microM), which reflects the condition found in the insect host. In contrast with hexokinases from other trypanosomatids, the enzyme exhibited a moderate sensitivity to inhibition by glucose 6-phosphate. This inhibition was competitive with respect to both ATP and glucose, indicating that an allosteric site for glucose 6-phosphate does not exist in this enzyme. The enzyme was also inhibited by inorganic pyrophosphate, the inhibition being higher than that observed for T. cruzi enzyme. As expected, the enzyme was localized, by immunofluorescence analysis, in glycosomes and is present in both promastigotes and true amastigotes obtained from hamster lesion. Hexokinase specific activity increased with the aging of promastigote culture, and this increment was related to glucose consumption. However, the level of the hexokinase protein remains constant as determined by Western blotting. Several hypotheses are discussed to explain this result.
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Affiliation(s)
- Miguel A Pabón
- Laboratorio de Enzimología de Parásitos, Centro de Ingeniería Genética, Facultad de Ciencias, Universidad de Los Andes, La Hechicera, Mérida, 5101, Venezuela
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