Oxidoreductases

  • Article
    | Open Access

    The human 2-oxoglutarate (2OG) oxygenases FIH and AspH are relevant drug targets. Here, the authors show that synthetic and naturally occurring 2OG derivatives can selectively modulate FIH and AspH activities, suggesting that these compounds may serve as a basis to develop 2OG oxygenase-targeting probes and drugs.

    • Yu Nakashima
    • , Lennart Brewitz
    •  & Christopher J. Schofield
  • Article
    | Open Access

    Catalytic enantioselective halocyclization of alkenes is an important bond forming tool and a key step in natural product biosynthesis, but so far no examples of the enzymatic counterpart of this reaction on simple achiral olefins have been reported. Here, the authors describe examples of engineered flavin-dependent halogenases that catalyze halolactonization of olefins with high enantioselectivity and near-native catalytic activity.

    • Dibyendu Mondal
    • , Brian F. Fisher
    •  & Jared C. Lewis
  • Article
    | Open Access

    Microbial oxidoreductases are key in biomass breakdown. Here, the authors expand the specificity and redox scope within fungal auxiliary activity 7 family (AA7) enzymes and show that AA7 oligosaccharide dehydrogenases can directly fuel cellulose degradation by lytic polysaccharide monooxygenases.

    • Majid Haddad Momeni
    • , Folmer Fredslund
    •  & Maher Abou Hachem
  • Article
    | Open Access

    Streptoseomycin is a potent antibiotic that contains a pentacyclic 5/14/10/6/6 ring system. Here, the authors report the enzymatic and non-enzymatic steps of the downstream modification of streptoseomycin biosynthesis and show a [6 + 4]-cycloaddition adduct as an unexpected biosynthetic intermediate.

    • Kai Biao Wang
    • , Wen Wang
    •  & Hui Ming Ge
  • Article
    | Open Access

    Human manganese superoxide dismutase (MnSOD) is an oxidoreductase that uses concerted proton and electron transfers to reduce the levels of superoxide radicals in mitochondria, but mechanistic insights into this process are limited. Here, the authors report neutron crystal structures of Mn3+SOD and Mn2+SOD, revealing changes in the protonation states of key residues in the enzyme active site during the redox cycle.

    • Jahaun Azadmanesh
    • , William E. Lutz
    •  & Gloria E. O. Borgstahl
  • Article
    | Open Access

    One goal of potato breeding is to reduce the accumulation of toxic solanidane glycoalkaloids. Here the authors show that potato DPS, a 2-oxoglutarate dependent dioxygenase, catalyzes ring rearrangement of a biosynthetic precursor to differentiate solanidanes from spirosolanes that are found in other solanaceous plants.

    • Ryota Akiyama
    • , Bunta Watanabe
    •  & Masaharu Mizutani
  • Article
    | Open Access

    Bacterial malic enzymes (ME) transform malate to pyruvate. One group, hybrid ME enzymes, are regulated by acetyl-CoA, linking the enzyme activity to the metabolic state of the cell. Structures of a representative hybrid ME MaeB reveal large conformational rearrangements that provide insight into the mechanism of allosteric inhibition by acetyl-CoA.

    • Christopher John Harding
    • , Ian Thomas Cadby
    •  & Andrew Lee Lovering
  • Article
    | Open Access

    The Pseudomonas aeruginosa lytic polysaccharide monooxygenase CbpD, prevalent in clinical isolates, has been proposed to act as a virulence factor. Here, the authors combine structural work, in silico simulations, enzymatic activity and in vitro and in vivo experiments to further delineate the role of CbpD and show that its deletion renders P. aeruginosa unable to establish a lethal systemic infection, leading to enhanced bacterial clearance in a mouse model of infection.

    • Fatemeh Askarian
    • , Satoshi Uchiyama
    •  & Gustav Vaaje-Kolstad
  • Article
    | Open Access

    An important type of post-translational protein modification is the conversion of peptidyl amino acid into enzyme cofactor. Here, the authors report functional and structural characterization of a flavoprotein monooxygenase essential for biosynthesis of cysteine tryptophylquinone (CTQ) cofactor.

    • Toshinori Oozeki
    • , Tadashi Nakai
    •  & Toshihide Okajima
  • Article
    | Open Access

    Dual oxidases (DUOXs), assembled from the catalytic DUOX and the auxiliary DUOXA subunits, produce hydrogen peroxide by transferring electrons from intracellular NADPH to extracellular oxygen in a calcium-activated manner. Here authors report the cryo-EM structures of human DUOX1-DUOXA1 complex in both high-calcium and low-calcium states.

    • Jing-Xiang Wu
    • , Rui Liu
    •  & Lei Chen
  • Article
    | Open Access

    Lytic polysaccharide monooxygenases (LPMOs) catalyze the hydroxylation of glycosidic bonds in polysaccharides, but the catalytic properties of these monocopper enzymes remain poorly characterized. Here authors employ competition between reference enzymes and LPMOs for the H2O2 co-substrate to kinetically characterize LPMO-catalyzed cellulose oxidation.

    • Riin Kont
    • , Bastien Bissaro
    •  & Priit Väljamäe
  • Article
    | Open Access

    The respiratory complex I (NADH:ubiquinone oxidoreductase) is a large redox-driven proton pump that initiates respiration in mitochondria. Here, the authors present the 3.0 Å cryo-EM structure of complex I from mouse heart mitochondria with the ubiquinone-analogue inhibitor piericidin A bound in the active site and with kinetic measurements and MD simulations they further show that this inhibitor acts competitively against the native ubiquinone-10 substrate.

    • Hannah R. Bridges
    • , Justin G. Fedor
    •  & Judy Hirst
  • Article
    | Open Access

    Monooxygenases catalyse the hydroxylation of C-H bonds using oxygen as a co-substrate, which, in turn, is unavailable for anaerobic bacteria. Here, the authors report a three-step reaction cascade involving two hydroxylases and one dehydratase which hydroxylate the C26 methyl group of cholesterol with water as a co-substrate.

    • Christian Jacoby
    • , Sascha Ferlaino
    •  & Matthias Boll
  • Article
    | Open Access

    The number of usable light-responsive enzymes is limited, despite the potential biotechnological applications. Here, the authors report a flavoprotein monooxygenase which is controllable by blue light illumination, and propose a mechanism involving protein-mediated radical photoreduction of FAD via a semiquinone intermediate.

    • Simon Ernst
    • , Stefano Rovida
    •  & Steffen L. Drees
  • Article
    | Open Access

    Production of inflammatory mediators by M1-polarized macrophages is thought to rely on suppression of mitochondrial metabolism in favor of glycolysis. Refining this concept, here the authors define metabolic targets of nitric oxide as responsible for the mitochondrial rewiring resulting from polarization.

    • Erika M. Palmieri
    • , Marieli Gonzalez-Cotto
    •  & Daniel W. McVicar
  • Article
    | Open Access

    Understanding enzyme active sites can elucidate fundamental enzymatic reaction pathways and inform designs for synthetic catalysts. Here, authors employ operando X-ray absorption spectroelectrochemistry to assess copper ions in bilirubin oxidase during oxygen reduction electrocatalysis.

    • Lucyano J. A. Macedo
    • , Ayaz Hassan
    •  & Frank N. Crespilho
  • Article
    | Open Access

    Reactive oxygen species (ROS) stimulate GLUT4-mediated glucose transport following contraction of isolated muscle, but it is not clear if this occurs in vivo. Here, the authors show in human volunteers that exercise induces ROS increase in muscle and, using loss of-function animal models, they demonstrate that NOX2 is a major ROS source required to stimulate glucose uptake during exercise.

    • Carlos Henríquez-Olguin
    • , Jonas R. Knudsen
    •  & Thomas E. Jensen
  • Article
    | Open Access

    Sulfonamide is in many important drugs yet is rare in nature and little is known about the synthesis of sulfonamide containing antibiotics. Here, the authors report on a detailed analysis of the biosynthesis machineries of the aminoacyl sulfonamide antibiotics.

    • Zhijuan Hu
    • , Takayoshi Awakawa
    •  & Ikuro Abe
  • Article
    | Open Access

    Soluble fumarate reductases are essential for eukaryotic cell survival under anaerobic conditions but their mechanism is not fully understood. Here, the authors present structural and enzymatic analyses of yeast fumarate reductase Osm1, elucidating the molecular basis of maintaining redox balance during anaerobiosis.

    • Sunghwan Kim
    • , Chang Min Kim
    •  & Hyun Ho Park
  • Article
    | Open Access

    The human enzyme MTHFR links the folate and methionine cycles, which are essential for the biosynthesis of nucleotides and proteins. Here, the authors present the crystal structure and biochemical analysis of human MTHFR, providing molecular insights into its function and regulation in higher eukaryotes.

    • D. Sean Froese
    • , Jolanta Kopec
    •  & Wyatt W. Yue
  • Article
    | Open Access

    Some prokaryotes use alternative respiratory chain complexes, such as the alternative complex III (ACIII), to generate energy. Here authors provide the cryoEM structure of ACIII from Rhodothermus marinus which shows the arrangement of cofactors and provides insights into the mechanism for energy transduction.

    • Joana S. Sousa
    • , Filipa Calisto
    •  & Manuela M. Pereira
  • Article
    | Open Access

    The mechanism for covalent flavinylation of flavoenzymes is still unclear. Here, the authors propose a mechanism based on the crystal structure of a flavinylation assembly intermediate of the E. coli respiratory Complex II comprising the E. coli FrdA subunit bound to covalent FAD and crosslinked with its assembly factor SdhE.

    • Pankaj Sharma
    • , Elena Maklashina
    •  & T. M. Iverson
  • Article
    | Open Access

    NADPH oxidase NOX4 has been linked to poor cancer survival. Here the authors show that NOX4 regulates drug resistance in renal cancer carcinoma by regulating PKM2 and that NOX4 activity is allosterically activated by reduced mitochondrial ATP levels thus coupling energy metabolism to drug resistance.

    • Karthigayan Shanmugasundaram
    • , Bijaya K. Nayak
    •  & Karen Block
  • Article
    | Open Access

    Catalytic mechanisms of enzymes are well understood, but achieving diverse reaction chemistries in re-engineered proteins can be difficult. Here the authors show a highly efficient and thermostable artificial enzyme that catalyzes a diverse array of substrate oxidations coupled to the reduction of H2O2.

    • Daniel W. Watkins
    • , Jonathan M. X. Jenkins
    •  & J. L. Ross Anderson
  • Article
    | Open Access

    Glutaredoxins have important roles in redox processes. Here the authors show that the enzymatic activity of glutaredoxins requires two distinct glutathione interactions sites, one recognizing the glutathione disulfide substrate and one activating glutathione as a reducing agent.

    • Patricia Begas
    • , Linda Liedgens
    •  & Marcel Deponte
  • Article
    | Open Access

    While reversal of lysine methylation on histone tails is a well-established mechanism to tune gene expression, the existence of a similar arginine demethylation process is controversial. Here, the authors show that some jumonji enzymes possess both lysine and arginine demethylase activity in vitro.

    • Louise J. Walport
    • , Richard J. Hopkinson
    •  & Christopher J. Schofield
  • Article
    | Open Access

    DNA methylation contributes to transcriptional silencing. Here, Groth et al.show that mutant plants defective in MTHFD1, an enzyme involved in folate metabolism, have a DNA hypomethylation phenotype highlighting the link between one-carbon metabolism and DNA methylation, which is mediated by SAM as a common methyl donor.

    • Martin Groth
    • , Guillaume Moissiard
    •  & Steven E. Jacobsen
  • Article
    | Open Access

    Xanthones are pharmacologically and biosynthetically intriguing compounds. Here, the authors identify two cytochrome P450 enzymes, which hydroxylate and cyclize the benzophenone precursor to either 1,3,7- or 1,3,5-trihydroxyxanthones, and pinpoint residues that determine the alternative regioselectivities.

    • Islam El-Awaad
    • , Marco Bocola
    •  & Ludger Beerhues
  • Article
    | Open Access

    The sensitivity of nitrogenase to oxygen is a major barrier to engineer biological nitrogen fixation into cereal crops by direct nif gene transfer. Here the authors use yeast to show that targeting nitrogenase Fe protein to the mitochondrial matrix overcomes the O2sensitivity impediment.

    • Gema López-Torrejón
    • , Emilio Jiménez-Vicente
    •  & Luis M. Rubio
  • Article
    | Open Access

    The enzyme G6PD generates the reductive metabolite NADPH, which has antioxidant effects, but has also been linked to tumour growth. Here the authors generate mice that modestly overexpress G6PD and report increased lifespan in females, and no negative effects on tumour formation in various genetic models.

    • Sandrina Nóbrega-Pereira
    • , Pablo J. Fernandez-Marcos
    •  & Manuel Serrano
  • Article
    | Open Access

    The [Mo:7Fe:9S:C] iron-molybdenum cofactor (FeMoco) of nitrogenase is a large metal cluster with an important role in biological nitrogen fixation. Here, the authors use spatially resolved refinement of the anomalous scattering contributions of the iron atoms to determine the resting-state electron distribution of FeMoco.

    • Thomas Spatzal
    • , Julia Schlesier
    •  & Oliver Einsle
  • Article
    | Open Access

    Evidence suggests that the TCA cycle enzyme complex succinate dehydrogenase (SDH) may be dispensable for cell proliferation in some cancer cells. Here the authors show that SDH deficient cells become dependent on the mitochondrial enzyme pyruvate carboxylase for aspartate production and proliferation.

    • Charlotte Lussey-Lepoutre
    • , Kate E. R. Hollinshead
    •  & Daniel A. Tennant
  • Article
    | Open Access

    FR171456 is a bioactive chemical produced by some microorganisms. Here, the authors identify the enzyme NSDHL of the sterol synthesis pathway as the molecular target of FR171456, rendering it the first compound to specifically target this class of enzyme in yeast and mammalian cells.

    • Stephen B. Helliwell
    • , Shantanu Karkare
    •  & Christian N. Parker
  • Article |

    Thioredoxin reductase 1 is a flavoprotein that is involved in the regulation of redox homeostasis. Fritz-Wolfet al. report the first crystal structures of thioredoxin reductase 1 in complex with its substrate, thioredoxin, and confirm that the enzyme uses a flexible carboxy-terminal arm for electron transport to its substrates.

    • Karin Fritz-Wolf
    • , Sebastian Kehr
    •  & Katja Becker
  • Article
    | Open Access

    The Q-cycle is thought to be an essential energetic component of the photosynthetic electron-transfer chain. Here, Chlamydomonas mutants with an inactive Q-cycle but normal levels ofb6fcomplexes are shown to display photosynthetic growth, demonstrating the dispensability of the Q-cycle in the oxygenic photosynthetic chain.

    • Alizée Malnoë
    • , Francis-André Wollman
    •  & Fabrice Rappaport
  • Article |

    Hydrogen production using photosynthetic bacteria is an appealing energy source, but typically the bacteria require anaerobic conditions. Here, the authors report a wild-type cyanobacterium strain that shows very high rates of hydrogen production under aerobic environmental conditions.

    • Anindita Bandyopadhyay
    • , Jana Stöckel
    •  & Himadri B. Pakrasi