Loss of ETHE1, a mitochondrial dioxygenase, causes fatal sulfide toxicity in ethylmalonic encephalopathy

Tiranti, Valeria; Viscomi, Carlo; Hildebrandt, Tatjana M.; Meo, Ivano Di; Mineri, Rossana; Tiveron, Cecilia; Levitt, Michael D.; Prelle, A.; Fagiolari, Gigliola; Rimoldi, M.; Zeviani, Massimo

doi:10.1038/nm.1907

Cited by 355 publications

(402 citation statements)

References 39 publications

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“…Conditions used were pH 7.0, 0.2 M NaCl, at 25.0°C. (28) and two of the four candidate rhodanese sulfur transferase domains in S. aureus (29) (CstA, NWMN_0027; CstB, NWMN_0028), a potential sulfur dioxygenase (CstB, NWMN_0027) (30), and a predicted sulfide quinone reductase (NWMN_0029) (see Fig. 3A) (31).…”

Section: Cstr (Nwmn_00265) Is a Repressor Of An Operon Predicted To mentioning

confidence: 99%

Control of Copper Resistance and Inorganic Sulfur Metabolism by Paralogous Regulators in Staphylococcus aureus

Grossoehme

Kehl-Fie

et al. 2011

Journal of Biological Chemistry

214

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All strains of Staphylococcus aureus encode a putative copper-sensitive operon repressor (CsoR) and one other CsoR-like protein of unknown function. We show here that NWMN_1991 encodes a bona fide Cu(I)-inducible CsoR of a genetically unlinked copA-copZ copper resistance operon in S. aureus strain Newman. In contrast, an unannotated open reading frame found between NWMN_0027 and NWMN_0026 (denoted NWMN_0026.5) encodes a CsoR-like regulator that represses expression of adjacent genes by binding specifically to a pair of canonical operator sites positioned in the NWMN_0027-0026.5 intergenic region. Inspection of these regulated genes suggests a role in assimilation of inorganic sulfur from thiosulfate and vectorial sulfur transfer, and we designate NWMN_ 0026.5 as CstR (CsoR-like sulfur transferase repressor). Expression analysis demonstrates that CsoR and CstR control their respective regulons in response to distinct stimuli with no overlap in vivo. Unlike CsoR, CstR does not form a stable complex with Cu(I); operator binding is instead inhibited by oxidation of the intersubunit cysteine pair to a mixture of disulfide and trisulfide linkages by a likely metabolite of thiosulfate assimilation, sulfite. CsoR is unreactive toward sulfite under the same conditions. We conclude that CsoR and CstR are paralogs in S. aureus that function in the same cytoplasm to control distinct physiological processes.The Gram-positive opportunistic human pathogen Staphylococcus aureus is the causative agent of a wide range of hospital and community-acquired infections that are associated with significant morbidity (1). With the incidence of methicillinresistant strains increasing in previously low prevalence areas (2), new antibiotic therapies that target novel metabolic pathways are urgently needed. One approach is to target those processes that allow a pathogen to respond to environmental stresses that might change depending on the microenvironmental host niche in which the organism finds itself. Resistance to host-mediated copper killing of Escherichia coli (3), Salmonella enterica (4), and Mycobacterium tuberculosis (5, 6) and sulfur assimilation and cysteine biosynthesis in M. tuberculosis (7,8) are two such processes. S. aureus is particularly sensitive to rapid killing when exposed to copper or copper alloy surfaces, justifying this therapeutic direction (9, 10).M. tuberculosis CsoR 6 (copper-sensitive operon repressor) is a founding member of large family of regulators now known collectively to respond to Cu(I), Ni(II), and perhaps other stressors, the structural basis of which is not fully understood (11, 12). All CsoR family proteins lack a known canonical DNA binding domain and are projected to adopt the flat disc-shaped dimer of dimers homotetrameric structure characteristic of Cu(I)-sensing CsoRs, with individual dimers consisting of an antiparallel four-helix bundle flanked by a C-terminal ␣3 helix (13,14). Two cysteine residues on opposite subunits within a dimer make coordination bonds to the Cu(I) ion, with the third ...

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Section: Cstr (Nwmn_00265) Is a Repressor Of An Operon Predicted To mentioning

confidence: 99%

Control of Copper Resistance and Inorganic Sulfur Metabolism by Paralogous Regulators in Staphylococcus aureus

Grossoehme

Kehl-Fie

et al. 2011

Journal of Biological Chemistry

214

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“…In EE, H 2 S and thiosulfate levels are increased (5). Inhibition of cytochrome c oxidase due to elevated H 2 S (24) impairs the sulfide oxidation pathway overall, as seen in EE patients and in ethe -/-mice (25).…”

Section: Discussionmentioning

confidence: 99%

“…Oxygen binding displaces a second water molecule and gives rise to the Fe(III)-superoxo complex [3], which exists in resonance with structure [4] in which the coordinated sulfur has a radical cation character. Recombination of the iron-coordinated sulfur leads to formation of a cyclic-peroxo intermediate [5]. Homolytic cleavage of the O-O bond results in a sulfoxy-cation and an Fe(II)-activated oxygen [6].…”

Section: Methodsmentioning

confidence: 99%

“…The latter, via resonance, gives a radical cation character to the coordinated sulfane sulfur on the substrate [4]. Recombination of the superoxo and sulfur radical species yields a cyclic peroxo intermediate [5], followed by homolytic cleavage of the O-O bond resulting in a sulfoxy-cation intermediate and an Fe(II)-bound activated oxygen [6]. Recombination of the activated oxygen and the sulfoxy-cation yields the GSSO 2 -intermediate [7], which is hydrolyzed to give the products, sulfite and GSH [8].…”

Section: Gssh + O + H O → Gsh + Somentioning

confidence: 99%

“…Mutations in PDO lead to an increase in the levels of thiosulfate and sulfide in EE patients and in ethe1 -/-mice (4,5). The majority of the patient mutations clusters around the iron-coordinating residues and the active site pocket suggesting that they disrupt metal and substrate binding and lead to enzyme destabilization.…”

Section: Gssh + O + H O → Gsh + Somentioning

confidence: 99%

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Mechanism-based inhibition of human persulfide dioxygenase by γ-glutamyl-homocysteinyl-glycine

Kabil

Motl

Strack

et al. 2018

Journal of Biological Chemistry

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Hydrogen sulfide (H 2 S) is a signaling molecule with many beneficial effects. However, its cellular concentration is strictly regulated to avoid toxicity. Persulfide dioxygenase (PDO or ETHE1) is a mononuclear non-heme ironcontaining protein in the sulfide oxidation pathway catalyzing the conversion of glutathione persulfide (GSSH) to sulfite and glutathione. PDO mutations result in the autosomal recessive disorder, ethylmalonic encephalopathy (EE). Here, we developed γ-glutamyl-homocysteinyl-glycine (GHcySH) in which the cysteinyl moiety in glutathione is substituted with homocysteine, as a mechanismbased PDO inhibitor. Human PDO used GHcySH as an alternate substrate and converted it to GHcy-SO 2 H, mimicking GS-SO 2 H, the putative oxygenated intermediate formed with the natural substrate. Since GHcy-SO 2 H contains a C-S bond rather than an S-S bond in GS-SO 2 H, it failed to undergo the final hydrolysis step in the catalytic cycle, leading to PDO inhibition. We also characterized the biochemical penalties incurred by the L55P, T136A, C161Y and R163W mutations reported in EE patients. The variants displayed lower iron content (1.4-to 11-fold) and lower thermal stability (1.2-to 1.7-fold) than wild-type PDO. They also exhibited varying degrees of catalytic impairment; the k cat /K m values for R163W, L55P and C161Y PDOs were 18-, 42-and 65-fold lower, respectively and the T136A variant was most affected with a 200-fold lower k cat /K m . Like wild-type enzyme, these variants were inhibited by GHcySH. This study provides the first characterization of an intermediate in the PDO-catalyzed reaction and reports on deficits associated with EE-linked mutations that are distal from the active site.Ethylmalonic encephalopathy (EE) 1 is an autosomal recessive disorder that is associated with pathological effects in the brain, gastrointestinal tract and peripheral vessels (1-3). It results in acrocyanosis, petechiae, hemorrhagic diarrhea, developmental delay and progressive neurological failure leading to necrotic lesions in the deep gray matter of the brain. Patients with EE usually succumb to the disease within the first decade of life (4). The clinical profile of EE includes elevated ethylmalonic acid in urine, C4 and C5 acrylcarnitines in blood and a deficiency of cytochrome c oxidase in brain and muscle (5). EE is caused by mutations in the ethe1 gene that encodes persulfide dioxygenase (PDO or ETHE1). Over 20 mutations have been described in the ethe1 gene, of which a subset represents missense mutations (3,4,6).PDO is a mitochondrial matrix protein that participates in the mitochondrial sulfide oxidation pathway, which converts H 2 S to the end products, thiosulfate and sulfate (7,8). In addition to PDO, the other enzymes involved in the mitochondrial sulfur oxidation pathway are sulfide quinone oxidoreductase (9), rhodanese (10), and sulfite oxidase (11). PDO catalyzes the second step in the pathway, i.e. the oxidation of glutathione persulfide (GSSH) to sulfite (Eq. 1) (12). Sulfite is either oxidized b...

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Mitochondrial Disorders: Nuclear Gene Mutations

Ghezzi

Zeviani

2011

Encyclopedia of Life Sciences

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In addition to mutations of mitochondrial deoxyribonucleic acid (mtDNA), many mitochondrial syndromes are due to abnormalities in nuclear genes related to oxidative phosphorylation (OXPHOS). Nuclear genes encode hundreds of proteins directly involved in mitochondrial OXPHOS or linked to other metabolic pathways that are related to OXPHOS, such as the tricarboxylic acid (TCA) cycle and fatty acids β‐oxidation, cell signalling and apoptosis. Although the identification of mutations in mtDNA has become relatively easy because its small size and the nearly complete elucidation of its sequence polymorphisms, the analysis of nuclear disease genes is still a formidable challenge. However, with the recent improvement in technology throughput and bio‐computational power, this scenario is rapidly changing. The discovery of several OXPHOS‐related human genes and the identification of mutations responsible for different clinical syndromes indicate that the majority, but not all, of the inherited mitochondrial disorders are due to nuclear genes encoding proteins targeted to mitochondria. Key Concepts: Mitochondria are the principal intracellular source of energy through the production of ATP by oxidative phosphorylation (OXPHOS). Mitochondria contain their own genome, a small, circular double‐stranded DNA (mtDNA). mtDNA contains 13 genes encoding subunits of the respiratory chain complexes and 24 genes encoding 2 ribosomal and 22 transfer RNAs, which are necessary to carry out intramitochondrial translation. Mitochondria depend on the nucleus for the supply of all of the other OXPHOS proteins as well as the factors necessary for replication, repair, transcription, translation, maintenance of mtDNA and for the biogenesis, shaping, fusion and fission of the organelles. Mitochondrial‐inherited diseases may present with a vast range of symptoms, severity, age of onset and outcome. Because of its dual genetic control, OXPHOS disorders can be due to mutations in mtDNA or nuclear DNA genes. Recent epidemiological studies show that mitochondrial disorders have a minimal prevalence of 1:5 000.

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Loss of ETHE1, a mitochondrial dioxygenase, causes fatal sulfide toxicity in ethylmalonic encephalopathy

Cited by 355 publications

References 39 publications

Control of Copper Resistance and Inorganic Sulfur Metabolism by Paralogous Regulators in Staphylococcus aureus

Control of Copper Resistance and Inorganic Sulfur Metabolism by Paralogous Regulators in Staphylococcus aureus

Mechanism-based inhibition of human persulfide dioxygenase by γ-glutamyl-homocysteinyl-glycine

Mitochondrial Disorders: Nuclear Gene Mutations

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