The Experts below are selected from a list of 35211 Experts worldwide ranked by ideXlab platform
Catherine L Drennan - One of the best experts on this subject based on the ideXlab platform.
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a structural phylogeny for understanding 2 oxoacid Oxidoreductase function
Current Opinion in Structural Biology, 2016Co-Authors: Marcus I Gibson, Percival Yangting Chen, Catherine L DrennanAbstract:2-Oxoacid:ferredoxin Oxidoreductases (OFORs) are essential enzymes in microbial one-carbon metabolism. They use thiamine pyrophosphate to reversibly cleave carbon–carbon bonds, generating low potential (∼−500 mV) electrons. Crystallographic analysis of a recently discovered OFOR, an oxalate Oxidoreductase (OOR), has provided a second view of OFOR architecture and active site composition. Using these recent structural data along with the previously determined structures of pyruvate:ferredoxin Oxidoreductase, structure–function relationships in this superfamily have been expanded and re-evaluated. Additionally, structural motifs have been defined that better serve to distinguish one OFOR subfamily from another and potentially uncover novel OFORs.
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the structure of an oxalate Oxidoreductase provides insight into microbial 2 oxoacid metabolism
Biochemistry, 2015Co-Authors: Marcus I Gibson, Edward J Brignole, Elizabeth Pierce, Mehmet Can, Stephen W Ragsdale, Catherine L DrennanAbstract:Thiamine pyrophosphate (TPP), a derivative of vitamin B1, is a versatile and ubiquitous cofactor. When coupled with [4Fe-4S] clusters in microbial 2-oxoacid:ferredoxin Oxidoreductases (OFORs), TPP is involved in catalyzing low-potential redox reactions that are important for the synthesis of key metabolites and the reduction of N2, H+, and CO2. We have determined the high-resolution (2.27 A) crystal structure of the TPP-dependent oxalate Oxidoreductase (OOR), an enzyme that allows microbes to grow on oxalate, a widely occurring dicarboxylic acid that is found in soil and freshwater and is responsible for kidney stone disease in humans. OOR catalyzes the anaerobic oxidation of oxalate, harvesting the low-potential electrons for use in anaerobic reduction and fixation of CO2. We compare the OOR structure to that of the only other structurally characterized OFOR family member, pyruvate:ferredoxin Oxidoreductase. This side-by-side structural analysis highlights the key similarities and differences that are re...
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The Structure of an Oxalate Oxidoreductase Provides Insight into Microbial 2‑Oxoacid Metabolism
2015Co-Authors: Marcus I. Gibson, Edward J Brignole, Elizabeth Pierce, Mehmet Can, Stephen W Ragsdale, Catherine L DrennanAbstract:Thiamine pyrophosphate (TPP), a derivative of vitamin B1, is a versatile and ubiquitous cofactor. When coupled with [4Fe-4S] clusters in microbial 2-oxoacid:ferredoxin Oxidoreductases (OFORs), TPP is involved in catalyzing low-potential redox reactions that are important for the synthesis of key metabolites and the reduction of N2, H+, and CO2. We have determined the high-resolution (2.27 Å) crystal structure of the TPP-dependent oxalate Oxidoreductase (OOR), an enzyme that allows microbes to grow on oxalate, a widely occurring dicarboxylic acid that is found in soil and freshwater and is responsible for kidney stone disease in humans. OOR catalyzes the anaerobic oxidation of oxalate, harvesting the low-potential electrons for use in anaerobic reduction and fixation of CO2. We compare the OOR structure to that of the only other structurally characterized OFOR family member, pyruvate:ferredoxin Oxidoreductase. This side-by-side structural analysis highlights the key similarities and differences that are relevant for the chemistry of this entire class of TPP-utilizing enzymes
James D Watson - One of the best experts on this subject based on the ideXlab platform.
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bioactivation of napabucasin triggers reactive oxygen species mediated cancer cell death
Annals of Oncology, 2019Co-Authors: Fieke Froeling, Iok In Christine Chio, Melissa Yao, Matthew S Lucito, Priya Alagesan, A Y Chang, Youngkyu Park, H A Rogoff, David A Tuveson, James D WatsonAbstract:Abstract Background Napabucasin (2-acetylfuro-1,4-naphthoquinone) is a small molecule currently being clinically evaluated in several different cancer types. It has mostly been recognized for its ability to inhibit STAT3-mediated gene expression with activity against bulk tumor cells, as well as cancer stem cells. However, based on its chemical structure, we hypothesized that napabucasin is a substrate for reduction by NAD(P)H:quinone Oxidoreductase-1 (NQO1) and therefore may exert its anti-cancer effect through redox cycling, resulting in reactive oxygen species (ROS) production and cell death. Methods Binding of napabucasin to NQO1, as well as other Oxidoreductases, was measured. Pancreatic cancer cell lines and xenografts were treated with napabucasin, and cell survival, ROS generation, glutathione to glutathione disulfide (GSH:GSSG) ratios and changes in STAT3 signaling were assayed. Genetic knockout or pharmacological inhibition with dicoumarol was used to evaluate the dependency on NQO1 in vitro and in vivo. Results Napabucasin was found to bind with high affinity to NQO1 and to a lesser degree to cytochrome P450 Oxidoreductase (POR). Differential cytotoxic effects were observed, where NQO1-expressing cells in particular were highly sensitive. Treatment resulted in significant induction of ROS with reduced GSH:GSSG ratios, increased DNA damage and an NQO1-dependent decrease in STAT3 phosphorylation. Cells with low or no baseline NQO1 expression also produced ROS in response to napabucasin treatment, albeit to a lesser degree, through the one-electron reductase POR. Conclusions Napabucasin is bioactivated by Oxidoreductases, in particular NQO1 and to a lesser extent POR, resulting in futile redox cycling and generation of cytotoxic levels of ROS. The increase in ROS has multiple intracellular effects, one of which is a reduction in STAT3 signaling, ultimately resulting in cell death. Legal entity responsible for the study The authors. Funding Lustgarten Foundation, National Institutes of Health, Donaldson Charitable Trust, Boston Biomedical Inc. Disclosure J. Li: Full / Part-time employment: Boston Biomedical, Inc. A. Chang: Full / Part-time employment: Boston Biomedical, Inc.. H.A. Rogoff: Full / Part-time employment: Boston Biomedical, Inc.. J.D. Watson: Advisory / Consultancy, The consultancy occured in the past: Boston Biomedical, Inc. All other authors have declared no conflicts of interest.
Hans K Lorenzo - One of the best experts on this subject based on the ideXlab platform.
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apoptosis inducing factor aif a phylogenetically old caspase independent effector of cell death
Cell Death & Differentiation, 1999Co-Authors: Hans K LorenzoAbstract:Although much emphasis has been laid on the role of caspase in cell death, recent data indicate that, in many instances, mammalian cell death is caspase-independent. Thus, in many examples of mammalian cell death the 'decision' between death and life is upstream or independent of caspase activation. Similarly, it is unclear whether PCD of plants and fungi involves the activation of caspase-like enzymes, and no caspase-like gene has thus far been cloned in these phyla. Apoptosis inducing factor (AIF) is a new mammalian, caspase-independent death effector which, upon apoptosis induction, translocates from its normal localization, the mitochondrial intermembrane space, to the nucleus. Once in the nucleus, AIF causes chromatin condensation and large scale DNA fragmentation to fragments of approximately 50 kbp. The AIF cDNA from mouse and man codes for a protein which possesses three domains (i) an amino-terminal presequence which is removed upon import into the intermembrane space of mitochondria; (ii) a spacer sequence of approximately 27 amino acids; and (iii) a carboxyterminal 484 amino acid Oxidoreductase domain with strong homology to Oxidoreductases from other vertebrates (X. laevis), non-vertebrate animals (C. elegans, D. melanogaster), plants, fungi, eubacteria, and archaebacteria. Functionally important amino acids involved in the interaction with the prosthetic groups flavin adenine nucleotide and nicotinamide adenine nucleotide are strongly conserved between AIF and bacterial Oxidoreductase. Several eukaryotes possess a similar domain organisation in their AIF homologs, making them candidates to be mitochondrial Oxidoreductases as well as caspase-independent death effectors. The phylogenetic implications of these findings are discussed.
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apoptosis inducing factor aif a phylogenetically old caspase independent effector of cell death
Cell Death & Differentiation, 1999Co-Authors: Hans K Lorenzo, Santos A Susin, Josef M Penninger, Guido KroemerAbstract:Although much emphasis has been laid on the role of caspase in cell death, recent data indicate that, in many instances, mammalian cell death is caspase-independent. Thus, in many examples of mammalian cell death the ‘decision’ between death and life is upstream or independent of caspase activation. Similarly, it is unclear whether PCD of plants and fungi involves the activation of caspase-like enzymes, and no caspase-like gene has thus far been cloned in these phyla. Apoptosis inducing factor (AIF) is a new mammalian, caspaseindependent death effector which, upon apoptosis induction, translocates from its normal localization, the mitochondrial intermembrane space, to the nucleus. Once in the nucleus, AIF causes chromatin condensation and large scale DNA fragmentation to fragments of *50 kbp. The AIF cDNA from mouse and man codes for a protein which possesses three domains (i) an amino-terminal presequence which is removed upon import into the intermembrane space of mitochondria; (ii) a spacer sequence of approximately 27 amino acids; and (iii) a carboxyterminal 484 amino acid Oxidoreductase domain with strong homology to Oxidoreductases from other vertebrates ( X. laevis), non-vertebrate animals (C.elegans, D. melanogaster ), plants, fungi, eubacteria, and archaebacteria. Functionally important amino acids involved in the interaction with the prosthetic groups flavin adenine nucleotide and nicotinamide adenine nucleotide are strongly conserved between AIF and bacterial Oxidoreductase. Several eukaryotes possess a similar domain organisation in their AIF homologs, making them candidates to be mitochondrial Oxidoreductases as well as caspase-independent death effectors. The phylogenetic implications of these findings are discussed.
Michael I Verkhovsky - One of the best experts on this subject based on the ideXlab platform.
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sodium translocating nadh quinone Oxidoreductase as a redox driven ion pump
Biochimica et Biophysica Acta, 2010Co-Authors: Michael I Verkhovsky, Alexander V BogachevAbstract:The Na+-translocating NADH:ubiquinone Oxidoreductase (Na+-NQR) is a component of the respiratory chain of various bacteria. This enzyme is an analogous but not homologous counterpart of mitochondrial Complex I. Na+-NQR drives the same chemistry and also uses released energy to translocate ions across the membrane, but it pumps Na+ instead of H+. Most likely the mechanism of sodium pumping is quite different from that of proton pumping (for example, it could not accommodate the Grotthuss mechanism of ion movement); this is why the enzyme structure, subunits and prosthetic groups are completely special. This review summarizes modern knowledge on the structural and catalytic properties of bacterial Na+-translocating NADH:quinone Oxidoreductases. The sequence of electron transfer through the enzyme cofactors and thermodynamic properties of those cofactors is discussed. The resolution of the intermediates of the catalytic cycle and localization of sodium-dependent steps are combined in a possible molecular mechanism of sodium transfer by the enzyme.
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na translocating nadh quinone Oxidoreductase progress achieved and prospects of investigations
Biochemistry, 2005Co-Authors: Alexander V Bogachev, Michael I VerkhovskyAbstract:Structural and catalytic properties of bacterial Na+-translocating NADH: quinone Oxidoreductases are briefly described. Special attention is given to studies on kinetics of the enzyme interaction with NADH and the role of sodium ions in this process. Based on the existing data, possible model mechanisms of sodium transfer by Na+-translocating NADH:quinone Oxidoreductase are proposed.
Alexander V Bogachev - One of the best experts on this subject based on the ideXlab platform.
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sodium translocating nadh quinone Oxidoreductase as a redox driven ion pump
Biochimica et Biophysica Acta, 2010Co-Authors: Michael I Verkhovsky, Alexander V BogachevAbstract:The Na+-translocating NADH:ubiquinone Oxidoreductase (Na+-NQR) is a component of the respiratory chain of various bacteria. This enzyme is an analogous but not homologous counterpart of mitochondrial Complex I. Na+-NQR drives the same chemistry and also uses released energy to translocate ions across the membrane, but it pumps Na+ instead of H+. Most likely the mechanism of sodium pumping is quite different from that of proton pumping (for example, it could not accommodate the Grotthuss mechanism of ion movement); this is why the enzyme structure, subunits and prosthetic groups are completely special. This review summarizes modern knowledge on the structural and catalytic properties of bacterial Na+-translocating NADH:quinone Oxidoreductases. The sequence of electron transfer through the enzyme cofactors and thermodynamic properties of those cofactors is discussed. The resolution of the intermediates of the catalytic cycle and localization of sodium-dependent steps are combined in a possible molecular mechanism of sodium transfer by the enzyme.
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na translocating nadh quinone Oxidoreductase progress achieved and prospects of investigations
Biochemistry, 2005Co-Authors: Alexander V Bogachev, Michael I VerkhovskyAbstract:Structural and catalytic properties of bacterial Na+-translocating NADH: quinone Oxidoreductases are briefly described. Special attention is given to studies on kinetics of the enzyme interaction with NADH and the role of sodium ions in this process. Based on the existing data, possible model mechanisms of sodium transfer by Na+-translocating NADH:quinone Oxidoreductase are proposed.
