Thiol-based redox metabolism of protozoan parasites

Müller, Sylke; Liebau, Eva; Walter, Rolf D.; Krauth‐Siegel, R. Luise

doi:10.1016/s1471-4922(03)00141-7

Cited by 205 publications

(142 citation statements)

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“…The trypanothione system is the electron donor for the synthesis of DNA precursors and is involved in the antioxidative defense in these parasites (5,34,35). As shown here, trypanothione replaces glutathione also in the glyoxalase system of African trypanosomes.…”

Section: Discussionmentioning

confidence: 56%

“…All these parasitic protozoa have in common that the nearly ubiquitous glutathione/glutathione reductase system is replaced by trypanothione (N 1 ,N 8 -bis(glutathionyl)spermidine) and the flavoenzyme trypanothione reductase (4,5). A linkage between glutathione and spermidine metabolism was first discovered in Escherichia coli (6).…”

mentioning

confidence: 99%

“…During stationary phase, all of the cellular spermidine and a large part of glutathione occur as mono(glutathionyl)spermidine whereby the bacterium does not form trypanothione. The trypanothione metabolism is essential for the parasite (7) and is involved in the detoxication of hydroperoxides, the synthesis of deoxyribonucleotides catalyzed by ribonucleotide reductase, as well as the homeostasis of ascorbate (5).…”

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confidence: 99%

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Glyoxalase II of African Trypanosomes Is Trypanothione-dependent

Irsch

Krauth‐Siegel

2004

Journal of Biological Chemistry

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The glyoxalase system is a ubiquitous pathway catalyzing the glutathione-dependent detoxication of ketoaldehydes such as methylglyoxal, which is mainly formed as a by-product of glycolysis. The gene encoding a glyoxalase II has been cloned from Trypanosoma brucei, the causative agent of African sleeping sickness. The deduced protein sequence contains the highly conserved metal binding motif THXHXDH but lacks three basic residues shown to fix the glutathione-thioester substrate in the crystal structure of human glyoxalase II. Recombinant T. brucei glyoxalase II hydrolyzes lactoylglutathione, but does not show saturation kinetics up to 5 mM with the classical substrate of glyoxalases II. Instead, the parasite enzyme strongly prefers thioesters of trypanothione (bis(glutathionyl)spermidine), which were prepared from methylglyoxal and trypanothione and analyzed by high performance liquid chromatography and mass spectrometry. The glyoxalase system is a ubiquitous pathway for the detoxication of highly reactive ketoaldehydes. Glyoxalase I (EC 4.4.1.5., lactoylglutathione methylglyoxal lyase) and glyoxalase II (EC 3.1.2.6., hydroxyacylglutathione hydrolase) catalyze the dismutation of 2-ketoaldehydes into the corresponding 2-hydroxy acids using glutathione as cofactor (1, 2). The main physiological function of the glyoxalase system is probably the detoxication of methylglyoxal, a mutagenic and cytotoxic compound that is mainly formed as a by-product of glycolysis. In addition, methylglyoxal is produced by the catabolism of amino acids via aminoacetone or hydroxyacetone (3). Methylglyoxal can react with the nucleophilic centers of DNA, RNA, and proteins. The ketoaldehyde reacts with the side chains of arginine, lysine, and cysteine and with the base guanine and to a lesser extent with adenine and cytosine. Glyoxalase I (GLX I) 1 converts the hemithioacetal, which is formed spontaneously from methylglyoxal and glutathione, into S-lactoylglutathione. The thioester is subsequently hydrolyzed by glyoxalase II (GLX II) yielding D-lactate and regenerating glutathione.Trypanosomatids are the causative agents of severe tropical diseases such as African sleeping sickness (Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense), Nagana cattle disease (T. brucei brucei and Trypanosoma congolense), Chagas' disease (Trypanosoma cruzi), and the three manifestations of leishmaniasis (Leishmania donovani, Leishmania major, and Leishmania mexicana). All these parasitic protozoa have in common that the nearly ubiquitous glutathione/glutathione reductase system is replaced by trypanothione (N 1 ,N 8 -bis(glutathionyl)spermidine) and the flavoenzyme trypanothione reductase (4,5). A linkage between glutathione and spermidine metabolism was first discovered in Escherichia coli (6). During stationary phase, all of the cellular spermidine and a large part of glutathione occur as mono(glutathionyl)spermidine whereby the bacterium does not form trypanothione. The trypanothione metabolism is essential for the parasite (7) and is involved...

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Section: Discussionmentioning

confidence: 56%

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confidence: 99%

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Glyoxalase II of African Trypanosomes Is Trypanothione-dependent

Irsch

Krauth‐Siegel

2004

Journal of Biological Chemistry

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“…Therefore, it was postulated that, in addition to detoxification, Pf-GST1 is involved in the sequestration of non-polymerized heme in the cytosol. The relative high concentration of Pf-GST1 in the parasite makes it plausible that the protein serves as an in vivo buffer for the parasitotoxic ferriprotoporphyrin IX in the cytosol (17) and that an inhibition of the ligandin would effectively kill the parasite. Interfering with heme detoxification and hemozoin formation is also the mode of action of the known antimalarial drug chloroquine.…”

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confidence: 99%

Native and Inhibited Structure of a Mu class-related Glutathione S-transferase from Plasmodium falciparum

Perbandt

Burmeister

Walter

et al. 2004

Journal of Biological Chemistry

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The parasite Plasmodium falciparum causes malaria tropica, the most prevailing parasitic disease worldwide, with 300 -500 million infections and 1.5-2.7 million deaths/year. The emergence of strains resistant to drugs used for prophylaxis and treatment and no vaccine available makes the structural analysis of potential drug targets essential. For that reason, we analyzed the three-dimensional structure of the glutathione S-transferase from P. falciparum (Pf-GST1) in the apoform and in complex with its inhibitor S-hexyl-glutathione. The structures have been analyzed to 2.6 and 2.2 Å, respectively. Pf-GST1 shares several structural features with the Mu-type GSTs and is therefore closely related to this class, even though alignments with its members display low sequence identities in the range of 20 -33%. Upon S-hexyl-glutathione binding, the overall structure and the glutathione-binding site (G-site) remain almost unchanged with the exception of the flexible C terminus. The detailed comparison of the parasitic enzyme with the human host Mu-class enzyme reveals that, although the overall structure is homologue, the shape of the hydrophobic binding pocket (H-site) differs substantially. In the human enzyme, it is shielded from one side by the large Mu-loop, whereas in Pf-GST1 the Mu-loop is truncated and the space to recognize and bind voluminous substrates is extended. This structural feature can be exploited to support the design of specific and parasite-selective inhibitors.Sophisticated defense strategies have evolved in organisms that enable them to deal with a broad range of foreign and endogenously derived toxic compounds. These structurally diverse usually highly non-polar molecules are by definition not required for normal metabolic functions, and enzyme systems that catalyze the rapid conversion of these compounds have been developed. However, instead of converting these compounds to useful metabolites as described for a vast array of highly specific enzymes among a large number of bacteria, higher life forms have opted for elimination of toxic compounds rather than their utilization (1). Generally, the pathways of detoxification can be divided into three phases. Phase I reactions consist of the so-called "functionalization" reactions, where a reactive group is demasked or introduced into the molecule. These reactive groups then can be conjugated with natural constituents of the organism (phase II) prior to excretion (phase III) (2).Glutathione S-transferases (GSTs, 1 EC 2.5.1.18) are a family of phase II detoxification enzymes found in most organisms. Eucaryotes usually contain multiple GSTs with different catalytic activities to accommodate a wide range of functions within the cells. Cytosolic GSTs of mammals are divided into seven classes named Alpha, Mu, Pi, Theta, Zeta, Sigma, and Omega on the basis of different amino sequences and substrate specificities. Additionally, the Kappa GST is a soluble mitochondrial enzyme. Studies of GSTs from non-mammalian species have revealed the existence of several ne...

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“…Effective therapeutic approaches for leishmaniasis may rely on unique biochemical characteristics that set trypanosomatids apart from other eukaryotic cells. Two of these features are the compartmentalization of glycolysis into a specific organelle, the glycosome (Michels et al, 2000;Hannaert et al, 2003), and the functional replacement of glutathione by trypanothione [N 1 ,N 8 -bis(glutathionyl)spermidine], a spermidine-glutathione conjugate (Mü ller et al, 2003;Flohé et al, 1999). By synergistically exploiting the disruption of trypanothione-dependent biochemical processes and the inhibition of the glycolytic pathway (Bakker et al, 1999), both of which are essential for parasite survival, new therapeutic targets may be identified.…”

Section: Introductionmentioning

confidence: 99%

Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of glyoxalase I fromLeishmania infantum

Barata¹,

Silva²,

Schuldt³

et al. 2010

Acta Cryst Sect F

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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 rodshaped form. While the cube-shaped form did not diffract X-rays at all, the rod-shaped form exhibited diffraction to about 2.0 Å 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 Å and three dimers of the enzyme per asymmetric unit.

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Thiol-based redox metabolism of protozoan parasites

Cited by 205 publications

References 68 publications

Glyoxalase II of African Trypanosomes Is Trypanothione-dependent

Glyoxalase II of African Trypanosomes Is Trypanothione-dependent

Native and Inhibited Structure of a Mu class-related Glutathione S-transferase from Plasmodium falciparum

Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of glyoxalase I fromLeishmania infantum

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