Molecular basis for resistance to antimycin and diuron, Q-cycle inhibitors acting at the Qi site in the mitochondrial ubiquinol-cytochrome c reductase in Saccharomyces cerevisiae.

Rago, J.P. Di; Colson, Anne‐Marie

doi:10.1016/s0021-9258(18)37792-5

Cited by 162 publications

(31 citation statements)

References 52 publications

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“…First, we investigated the effect of cytochrome b inhibitors on OCR levels. Antimycin A , and IDI-5918 inhibit cytochrome b by binding to its Qi site, and atovaquone, decoquinate, and BTZ-1 inhibit it by binding to the ubiquinol oxidation site (Qo site). These inhibitors were added in three doses to parasites in unbuffered RPMI, and the resultant OCR changes were monitored for 45 min.…”

Section: Resultsmentioning

confidence: 99%

A Novel Methodology for Bioenergetic Analysis of Plasmodium falciparum Reveals a Glucose-Regulated Metabolic Shift and Enables Mode of Action Analyses of Mitochondrial Inhibitors

Sakata‐Kato

Wirth

2016

ACS Infect. Dis.

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Given that resistance to all drugs in clinical use has arisen, discovery of new antimalarial drug targets is eagerly anticipated. The Plasmodium mitochondrion has been considered a promising drug target largely based on its significant divergence from the host organelle as well as its involvement in ATP production and pyrimidine biosynthesis. However, the functions of Plasmodium mitochondrial protein complexes and associated metabolic pathways are not fully characterized. Here, we report the development of novel and robust bioenergetic assay protocols for Plasmodium falciparum asexual parasites utilizing a Seahorse Bioscience XFe24 Extracellular Flux Analyzer. These protocols allowed us to simultaneously assess the direct effects of metabolites and inhibitors on mitochondrial respiration and glycolytic activity in real-time with the readout of oxygen consumption rate and extracellular acidification rate. Using saponin-freed parasites at the schizont stage, we found that succinate, malate, glycerol-3-phosphate, and glutamate, but not pyruvate, were able to increase the oxygen consumption rate and that glycerol-3-phosphate dehydrogenase had the largest potential as an electron donor among tested mitochondrial dehydrogenases. Furthermore, we revealed the presence of a glucose-regulated metabolic shift between oxidative phosphorylation and glycolysis. We measured proton leak and reserve capacity and found bioenergetic evidence for oxidative phosphorylation in erythrocytic stage parasites but at a level much lower than that observed in mammalian cells. Lastly, we developed an assay platform for target identification and mode of action studies of mitochondria-targeting antimalarials. This study provides new insights into the bioenergetics and metabolomics of the Plasmodium mitochondria.

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Section: Resultsmentioning

confidence: 99%

A Novel Methodology for Bioenergetic Analysis of Plasmodium falciparum Reveals a Glucose-Regulated Metabolic Shift and Enables Mode of Action Analyses of Mitochondrial Inhibitors

Sakata‐Kato

Wirth

2016

ACS Infect. Dis.

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“…No structural data is available for its binding mode. The mechanism of action, through inhibition of the Q i site, is known from genetic analysis of diurone- and antimycin-resistant mutations in the yeast model , and comparative kinetic studies …”

Section: Inhibitorsmentioning

confidence: 99%

Catalytic Reactions and Energy Conservation in the Cytochrome bc₁ and b₆f Complexes of Energy-Transducing Membranes

et al. 2021

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This review focuses on key components of respiratory and photosynthetic energy-transduction systems: the cytochrome bc 1 and b 6 f (Cytbc 1 /b 6 f) membranous multisubunit homodimeric complexes. These remarkable molecular machines catalyze electron transfer from membranous quinones to water-soluble electron carriers (such as cytochromes c or plastocyanin), coupling electron flow to proton translocation across the energy-transducing membrane and contributing to the generation of a transmembrane electrochemical potential gradient, which powers cellular metabolism in the majority of living organisms. Cytsbc 1 /b 6 f share many similarities but also have significant differences. While decades of research have provided extensive knowledge on these enzymes, several important aspects of their molecular mechanisms remain to be elucidated. We summarize a broad range of structural, mechanistic, and physiological aspects required for function of Cytbc 1 /b 6 f, combining textbook fundamentals with new intriguing concepts that have emerged from more recent studies. The discussion covers but is not limited to (i) mechanisms of energy-conserving bifurcation of electron pathway and energy-wasting superoxide generation at the quinol oxidation site, (ii) the mechanism by which semiquinone is stabilized at the quinone reduction site, (iii) interactions with substrates and specific inhibitors, (iv) intermonomer electron transfer and the role of a dimeric complex, and (v) higher levels of organization and regulation that involve Cytsbc 1 /b 6 f. In addressing these topics, we point out existing uncertainties and controversies, which, as suggested, will drive further research in this field.

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“…Resistance to antimycin A in Saccharomyces cerevisiae 27 Resistance Factor Whereas cross-resistance between illicicolin H, antimycin A and picolinamides was seen for L198F and G37 substitutions, differences between ilicicolin H and the other ligands were apparent for N31K, which did not confer resistance to ilicicolin H, and for Q22E which strongly reduced sensitivity to Ilicicolin H but did not affect the other inhibitors.…”

Section: K228mmentioning

confidence: 99%

Interaction of picolinamide fungicide primary metabolites UK‐2A and CAS‐649 with the cytochrome bc₁ complex Qi site: mutation effects and modelling in Saccharomyces cerevisiae

Young

Meunier

Wang

2022

Pest Management Science

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BACKGROUND: Fenpicoxamid and florylpicoxamid are picolinamide fungicides targeting the Qi site of the cytochrome bc 1 complex, via their primary metabolites UK-2A and CAS-649, respectively. We explore binding interactions and resistance mechanisms for picolinamides, antimycin A and ilicicolin H in yeast by testing effects of cytochrome b amino acid changes on fungicide sensitivity and interpreting results using molecular docking.RESULTS: Effects of amino acid changes on sensitivity to UK-2A and CAS-649 were similar, with highest resistance associated with exchanges involving G37 and substitutions N31K and L198F. These changes, as well as K228M, also affected antimycin A, while ilicicolin H was affected by changes at G37 and L198, as well as Q22E. N31 substitution patterns suggest that a lysine at position 31 introduces an electrostatic interaction with neighbouring D229, causing disruption of a key salt-bridge interaction with picolinamides. Changes involving G37 and L198 imply resistance primarily through steric interference. G37 changes also showed differences between CAS-649 and UK-2A or antimycin A with respect to branched versus unbranched amino acids. N31K and substitution of G37 by large amino acids reduced growth rate substantially while L198 substitutions showed little effect on growth.CONCLUSION: Binding of UK-2A and CAS-649 at the Qi site involves similar interactions such that general cross-resistance between fenpicoxamid and florylpicoxamid is anticipated in target pathogens. Some resistance mutations reduced growth rate and could carry a fitness penalty in pathogens. However, certain changes involving G37 and L198 carry little or no growth penalty and may pose the greatest risk for resistance development in the field.

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Molecular basis for resistance to antimycin and diuron, Q-cycle inhibitors acting at the Qi site in the mitochondrial ubiquinol-cytochrome c reductase in Saccharomyces cerevisiae.

Cited by 162 publications

References 52 publications

A Novel Methodology for Bioenergetic Analysis of Plasmodium falciparum Reveals a Glucose-Regulated Metabolic Shift and Enables Mode of Action Analyses of Mitochondrial Inhibitors

A Novel Methodology for Bioenergetic Analysis of Plasmodium falciparum Reveals a Glucose-Regulated Metabolic Shift and Enables Mode of Action Analyses of Mitochondrial Inhibitors

Catalytic Reactions and Energy Conservation in the Cytochrome bc₁ and b₆f Complexes of Energy-Transducing Membranes

Interaction of picolinamide fungicide primary metabolites UK‐2A and CAS‐649 with the cytochrome bc₁ complex Qi site: mutation effects and modelling in Saccharomyces cerevisiae

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Molecular basis for resistance to antimycin and diuron, Q-cycle inhibitors acting at the Qi site in the mitochondrial ubiquinol-cytochrome c reductase in Saccharomyces cerevisiae.

Cited by 162 publications

References 52 publications

A Novel Methodology for Bioenergetic Analysis of Plasmodium falciparum Reveals a Glucose-Regulated Metabolic Shift and Enables Mode of Action Analyses of Mitochondrial Inhibitors

A Novel Methodology for Bioenergetic Analysis of Plasmodium falciparum Reveals a Glucose-Regulated Metabolic Shift and Enables Mode of Action Analyses of Mitochondrial Inhibitors

Catalytic Reactions and Energy Conservation in the Cytochrome bc1 and b6f Complexes of Energy-Transducing Membranes

Interaction of picolinamide fungicide primary metabolites UK‐2A and CAS‐649 with the cytochrome bc1 complex Qi site: mutation effects and modelling in Saccharomyces cerevisiae

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Catalytic Reactions and Energy Conservation in the Cytochrome bc₁ and b₆f Complexes of Energy-Transducing Membranes

Interaction of picolinamide fungicide primary metabolites UK‐2A and CAS‐649 with the cytochrome bc₁ complex Qi site: mutation effects and modelling in Saccharomyces cerevisiae