<i>Trypanosoma Cruzi</i>trypanothione reductase is inactivated by peroxidase-generated phenothiazine cationic radicals

Gutiérrez-Correa, José; Fairlamb, Alan H.; Stoppani, A. O. M.

doi:10.1080/10715760100300311

Cited by 46 publications

(27 citation statements)

References 42 publications

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“…In this mutant, the substituted Cys, which is generally a more suitable ligand of iron-sulfur clusters, seemed to ligate to the iron-sulfur cluster. However, the H106C mutant could not maintain the stability of the iron-sulfur clusters as in the wild type subunit (44). The loss of ligand in the H106A mutant resulted in almost no incorporation of all iron-sulfur clusters into the subunit.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Cluster N5 as a Fast-relaxing [4Fe-4S] Cluster in the Nqo3 Subunit of the Proton-translocating NADH-ubiquinone Oxidoreductase from Paracoccus denitrificans

Yano

Nakamaru‐Ogiso

et al. 2003

Journal of Biological Chemistry

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The NADH-quinone oxidoreductase from Paracoccus denitrificans consists of 14 subunits (Nqo1-14) and contains one FMN and eight iron-sulfur clusters. The Nqo3 subunit possesses fully conserved 11 Cys and 1 His in its N-terminal region and is considered to harbor three iron-sulfur clusters; however, only one binuclear (N1b) and one tetranuclear (N4) were previously identified. In this study, The energy-transducing NADH-quinone oxidoreductase is located at an entry point of the respiratory chain of mitochondria and bacteria, and catalyzes the redox coupled H ϩ or Na ϩ ion transport reaction (1). The enzyme complex is one of the largest and most complicated membrane-bound respiratory chain enzymes ever known. Mitochondrial enzyme (complex I) is composed of at least 46 subunits (2, 3), whereas the bacterial counterpart (NDH-1) such as those from Paracoccus denitrificans and Thermus thermophilus consists of only 14 subunits (4). All 14 subunits of the NDH-1 are homologous to their mitochondrial counterparts. Complex I/NDH-1 share many structural and enzymatic properties. Complex I/NDH-1 is composed of two distinct domains, a hydrophilic extramembrane domain (promontory part) and a hydrophobic membrane domain. Each domain plays a distinct role in the energy transducing reaction (5-9). Generally, the enzyme complexes contain the same type and number of redox components: one non-covalently bound FMN and up to eight iron-sulfur clusters (10). All of these redox cofactors are located in the promontory part where the oxidation of NADH and the subsequent electron transfer reaction takes place toward the membrane part. In the membrane part, a lipid-soluble quinone molecule accepts electrons. In this terminal reaction step, some membrane-bound quinone species are suggested to be involved (11, 12); however, these quinone-binding sites remain to be located. These redox reactions are endergonic, releasing free energy that is used to transport ions (H ϩ or Na ϩ ) through channels, which are thought to traverse the membrane domain. In the case of bovine heart mitochondrial complex I, ϳ4 H ϩ are transported during the electron transfer from NADH to quinone pool. However, the energy coupling mechanism has not been solved experimentally. The understanding of this process is a crucial issue of complex I bioenergetics.Among the eight iron-sulfur clusters common in complex I/NDH-1 family, six clusters are generally detectable by EPR spectroscopy in situ, namely two [2Fe-2S] clusters, N1a and N1b, and four [4Fe-4S] clusters, N2, N3, N4, and N5 (10). Thus far, subunit locations of clusters N1a, N1b, N3, and N4 have tentatively been assigned based upon biochemical/physicochemical investigations of mammalian and microorganisms (10) and a series of expression studies of the individual putative iron-sulfur cluster-binding subunits of the P. denitrificans enzyme (13-15). Furthermore, two additional [4Fe-4S] clusters, which have not been detected by EPR in situ, are coordinated in the TYKY/Nqo9/NuoI subunit (nomenclature used for bovine heart mi...

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Section: Discussionmentioning

confidence: 99%

Characterization of Cluster N5 as a Fast-relaxing [4Fe-4S] Cluster in the Nqo3 Subunit of the Proton-translocating NADH-ubiquinone Oxidoreductase from Paracoccus denitrificans

Yano

Nakamaru‐Ogiso

et al. 2003

Journal of Biological Chemistry

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“…Haloperidol, an antipsychotic drug associated with the blockade of postsynaptic dopamine D2 receptors, is also active against Toxoplasma gondii (38) and was previously reported as inactive against the trypomastigote form of T. cruzi (37). Fluphenazine is a member of the phenothiazines that has been shown to inhibit the growth of T. brucei in vitro (58) but was inactive (36) or weakly active (6) against the T. cruzi enzyme trypanothione reductase. Carvedilol, a ␤-adrenergic receptor blocker, was demonstrated to improve Chagas' cardiomyopathy in patients when added to treatment with renin-angiotensin system (RAS) inhibitors (10).…”

Section: Discussionmentioning

confidence: 99%

Image-Based High-Throughput Drug Screening Targeting the Intracellular Stage of Trypanosoma cruzi , the Agent of Chagas' Disease

Engel¹,

Ang

Chen

et al. 2010

Antimicrob Agents Chemother

102

114

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Chagas' disease, caused by infection with the parasite Trypanosoma cruzi, is the major cause of heart failure in Latin America. Classic clinical manifestations result from the infection of heart muscle cells leading to progressive cardiomyopathy. To ameliorate disease, chemotherapy must eradicate the parasite. Current drugs are ineffective and toxic, and new therapy is a critical need. To expedite drug screening for this neglected disease, we have developed and validated a cell-based, high-throughput assay that can be used with a variety of untransfected T. cruzi isolates and host cells and that simultaneously measures efficacy against the intracellular amastigote stage and toxicity to host cells. T. cruzi-infected muscle cells were incubated in 96-well plates with test compounds. Assay plates were automatically imaged and analyzed based on size differences between the DAPI (4,6-diamidino-2-phenylindole)-stained host cell nuclei and parasite kinetoplasts. A reduction in the ratio of T. cruzi per host cell provided a quantitative measure of parasite growth inhibition, while a decrease in count of the host nuclei indicated compound toxicity. The assay was used to screen a library of clinically approved drugs and identified 55 compounds with activity against T. cruzi. The flexible assay design allows the use of various parasite strains, including clinical isolates with different biological characteristics (e.g., tissue tropism and drug sensitivity), and a broad range of host cells and may even be adapted to screen for inhibitors against other intracellular pathogens. This high-throughput assay will have an important impact in antiparasitic drug discovery.

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“…Experimental studies of T. cruzi have identified novel targets for chemotherapy, such as the enzyme trypanothione reductase (TR) [3]. Thioridazine (THI) is a phenothiazine that has been showed to be one of the most potent phenothiazines to inhibit TR irreversibly [4]. The results of exposing trypomastigotes and epimastigotes to THI in vitro and of treating lethal T. cruzi infection in mice with THI confirmed that the drug is trypanocidal, probably via its anticalmodulin effect [5,6].…”

Section: Introductionmentioning

confidence: 99%

Thioridazine treatment prevents cardiopathy in Trypanosoma cruzi infected mice

Presti

Rivarola

Bustamante

et al. 2004

International Journal of Antimicrobial Agents

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Trypanosoma Cruzitrypanothione reductase is inactivated by peroxidase-generated phenothiazine cationic radicals

Cited by 46 publications

References 42 publications

Characterization of Cluster N5 as a Fast-relaxing [4Fe-4S] Cluster in the Nqo3 Subunit of the Proton-translocating NADH-ubiquinone Oxidoreductase from Paracoccus denitrificans

Characterization of Cluster N5 as a Fast-relaxing [4Fe-4S] Cluster in the Nqo3 Subunit of the Proton-translocating NADH-ubiquinone Oxidoreductase from Paracoccus denitrificans

Image-Based High-Throughput Drug Screening Targeting the Intracellular Stage of Trypanosoma cruzi , the Agent of Chagas' Disease

Thioridazine treatment prevents cardiopathy in Trypanosoma cruzi infected mice

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