Author
Vincent Nivière
Other affiliations: University of Grenoble, Centre national de la recherche scientifique
Bio: Vincent Nivière is an academic researcher from Joseph Fourier University. The author has contributed to research in topics: Superoxide reductase & Active site. The author has an hindex of 25, co-authored 38 publications receiving 1647 citations. Previous affiliations of Vincent Nivière include University of Grenoble & Centre national de la recherche scientifique.
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TL;DR: This work trapped iron(III)-(hydro)peroxo species in crystals of superoxide reductase (SOR), a nonheme mononuclear iron enzyme that scavenges superoxide radicals.
Abstract: Iron-peroxide intermediates are central in the reaction cycle of many iron-containing biomolecules. We trapped iron(III)-(hydro)peroxo species in crystals of superoxide reductase (SOR), a nonheme mononuclear iron enzyme that scavenges superoxide radicals. X-ray diffraction data at 1.95 angstrom resolution and Raman spectra recorded in crystallo revealed iron-(hydro)peroxo intermediates with the (hydro)peroxo group bound end-on. The dynamic SOR active site promotes the formation of transient hydrogen bond networks, which presumably assist the cleavage of the iron-oxygen bond in order to release the reaction product, hydrogen peroxide.
133 citations
TL;DR: In this article, the authors showed that desulfoferrodoxin behaves as a superoxide reductase enzyme and thus provides new insights into the biological mechanisms designed for protection from oxidative stresses.
132 citations
TL;DR: UV-visible and electron paramagnetic resonance spectroscopy studies revealed that the ferrous center of desulfoferrodoxin could specifically and efficiently reduce O⨪2, with a rate constant of 6–7 × 108 m −1 s−1, and it was shown that membrane and cytoplasmic E. coli protein extracts, using NADH and NADPH as electron donors, could reduce the O⩪2oxidized form of des sulfuroferrod toxin.
Abstract: Desulfoferrodoxin is a small protein found in sulfate-reducing bacteria that contains two independent mononuclear iron centers, one ferric and one ferrous. Expression of desulfoferrodoxin from Desulfoarculus baarsii has been reported to functionally complement a superoxide dismutase deficient Escherichia coli strain. To elucidate by which mechanism desulfoferrodoxin could substitute for superoxide dismutase in E. coli, we have purified the recombinant protein and studied its reactivity toward O-(2). Desulfoferrodoxin exhibited only a weak superoxide dismutase activity (20 units mg(-1)) that could hardly account for its antioxidant properties. UV-visible and electron paramagnetic resonance spectroscopy studies revealed that the ferrous center of desulfoferrodoxin could specifically and efficiently reduce O-(2), with a rate constant of 6-7 x 10(8) M(-1) s(-1). In addition, we showed that membrane and cytoplasmic E. coli protein extracts, using NADH and NADPH as electron donors, could reduce the O-(2) oxidized form of desulfoferrodoxin. Taken together, these results strongly suggest that desulfoferrodoxin behaves as a superoxide reductase enzyme and thus provide new insights into the biological mechanisms designed for protection from oxidative stresses.
127 citations
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TL;DR: In this article, X-ray diffraction data at 1.95 angstrom resolution and Raman spectra recorded in crystallo revealed iron-peroxide intermediates with the (hydro)peroxo group bound end-on.
Abstract: Iron-peroxide intermediates are central in the reaction cycle of many iron-containing biomolecules. We trapped iron(III)-(hydro)peroxo species in crystals of superoxide reductase (SOR), a nonheme mononuclear iron enzyme that scavenges superoxide radicals. X-ray diffraction data at 1.95 angstrom resolution and Raman spectra recorded in crystallo revealed iron-(hydro)peroxo intermediates with the (hydro)peroxo group bound end-on. The dynamic SOR active site promotes the formation of transient hydrogen bond networks, which presumably assist the cleavage of the iron-oxygen bond in order to release the reaction product, hydrogen peroxide.
123 citations
TL;DR: Structural requirements for recognition of flavins as substrates and not as cofactors were studied by steady-state kinetics with a variety of flavin analogs and the entire isoalloxazine ring was found to be the essential part of the flavin molecule for interaction with the polypeptide chain.
112 citations
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28 Jul 2005
TL;DR: PfPMP1）与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。
18,940 citations
TL;DR: When considering new sensory technologies one should look to nature for guidance, as living organisms have developed the ultimate chemical sensors.
Abstract: When considering new sensory technologies one should look to nature for guidance. Indeed, living organisms have developed the ultimate chemical sensors. Many insects can detect chemical signals with perfect specificity and incredible sensitivity. Mammalian olfaction is based on an array of less discriminating sensors and a memorized response pattern to identify a unique odor. It is important to recognize that the extraordinary sensory performance of biological systems does not originate from a single element. In actuality, their performance is derived from a completely interactive system wherein the receptor is served by analyte delivery and removal mechanisms, selectivity is derived from receptors, and sensitivity is the result of analyte-triggered biochemical cascades. Clearly, optimal artificial sensory sys-
3,464 citations
Cold Spring Harbor Laboratory1, Emory University2, University of Washington3, National Institutes of Health4, North Shore-LIJ Health System5, University of Tampere6, Vanderbilt University7, Columbia University8, University College London9, University of California, Los Angeles10, University of Chicago11, Albert Einstein College of Medicine12
TL;DR: Findings establish de novo germline mutation as a more significant risk factor for ASD than previously recognized.
Abstract: We tested the hypothesis that de novo copy number variation (CNV) is associated with autism spectrum disorders (ASDs). We performed comparative genomic hybridization (CGH) on the genomic DNA of patients and unaffected subjects to detect copy number variants not present in their respective parents. Candidate genomic regions were validated by higher-resolution CGH, paternity testing, cytogenetics, fluorescence in situ hybridization, and microsatellite genotyping. Confirmed de novo CNVs were significantly associated with autism (P = 0.0005). Such CNVs were identified in 12 out of 118 (10%) of patients with sporadic autism, in 2 out of 77 (3%) of patients with an affected first-degree relative, and in 2 out of 196 (1%) of controls. Most de novo CNVs were smaller than microscopic resolution. Affected genomic regions were highly heterogeneous and included mutations of single genes. These findings establish de novo germline mutation as a more significant risk factor for ASD than previously recognized.
2,770 citations
TL;DR: The TrxR-catalyzed regeneration of several antioxidant compounds, including ascorbic acid (vitamin C), selenium-containing substances, lipoic acid, and ubiquinone are summarized.
2,632 citations
TL;DR: The field of antioxidants and free radicals is often perceived as focusing around the use of antioxidant supplements to prevent human disease, but in fact, antioxidants/free radicals permeate the whole of life, creating the field of redox biology.
Abstract: The field of antioxidants and free radicals is often perceived as focusing around the use of antioxidant supplements to prevent human disease. In fact, antioxidants/free radicals permeate the whole of life, creating the field of redox biology. Free radicals are not all bad, nor antioxidants all good
2,034 citations