Structural and mechanistic basis of the central energy-converting methyltransferase complex of methanogenesis.

Methanogenic archaea inhabiting anaerobic environments play a crucial role in the global biogeochemical material cycle. The most universal electrogenic reaction of their methane-producing energy metabolism is catalyzed by -methyl-tetrahydromethanopterin: coenzyme M methyltransferase (MtrABCDEFGH), which couples the vectorial Na transport with a methyl transfer between the one-carbon carriers tetrahydromethanopterin and coenzyme M via a vitamin B derivative (cobamide) as prosthetic group. We present the 2.

Growth of carbon nanotubes over carbon nanofibers catalyzed by bimetallic alloy nanoparticles as a bifunctional electrode for Zn-air batteries.

Design of economical, large-scale, stable, and highly active bifunctional electrocatalysts for Zn-air batteries with enhanced oxygen reduction and oxygen evolution performance is needed. Herein, a series of electrocatalysts were facilely fabricated where formed bimetallic nanoparticles aided in the growth of carbon nanotubes over carbon nanofibers (MM'-CNT@CNF) during thermal treatment. Different combinations of Fe, Ni, Co and Mn metals and melamine as precursor for CNT growth were investigated.

Electrospun aluminum silicate nanofibers as novel support material for immobilization of alcohol dehydrogenase.

Ceramic materials with high surface area, large and open porosity are considered excellent supports for enzyme immobilization owing to their stability and reusability. The present study reports the electrospinning of aluminum silicate nanofiber supports from sol-gel precursors, the impact of different fabrication parameters on the microstructure of the nanofibers and their performance in enzyme immobilization. A change in nanofiber diameter and pore size of the aluminum silicate nanofibers was observed upon varying specific processing parameters, such as the sol-composition (precursor and polymer concentration), the electrospinning parameters and the subsequent heat treatment (calcination temperature).

The molybdenum storage protein forms and deposits distinct polynuclear tungsten oxygen aggregates.

Some N-fixing bacteria store Mo to maintain the formation of the vital FeMo-cofactor dependent nitrogenase under Mo depleting conditions. The Mo storage protein (MoSto), developed for this purpose, has the unique capability to compactly deposit molybdate as polyoxometalate (POM) clusters in a (αβ) hexameric cage; the same occurs with the physicochemically related tungstate. To explore the structural diversity of W-based POM clusters, MoSto loaded under different conditions with tungstate and two site-specifically modified MoSto variants were structurally characterized by X-ray crystallography or single-particle cryo-EM.

Nanostructured carbons containing FeNi/NiFeO supported over N-doped carbon nanofibers for oxygen reduction and evolution reactions.

Non-precious metal-based electrocatalysts on carbon materials with high durability and low cost have been developed to ameliorate the oxygen-reduction reaction (ORR) and oxygen-evolution reaction (OER) for electrochemical energy applications such as in fuel cells and water electrolysis. Herein, two different morphologies of FeNi/NiFeO supported over hierarchical N-doped carbons were achieved carbonization of the polymer nanofibers by controlling the ratio of metal salts to melamine: a mixture of carbon nanotubes (CNTs) and graphene nanotubes (GNTs) supported over carbon nanofibers (CNFs) with spherical FeNi encapsulated at the tips (G/CNT@NCNF, 1 : 3), and graphene sheets wrapped CNFs with embedded needle-like FeNi (GS@NCNF, 2 : 3). G/CNT@NCNF shows excellent ORR activity (on-set potential: 0.

A Phosphofructokinase Homolog from Pyrobaculum calidifontis Displays Kinase Activity towards Pyrimidine Nucleosides and Ribose 1-Phosphate.

The genome of the hyperthermophilic archaeon contains an open reading frame, Pcal_0041, annotated as encoding a PfkB family ribokinase, consisting of phosphofructokinase and pyrimidine kinase domains. Among the biochemically characterized enzymes, the Pcal_0041 protein was 37% identical to the phosphofructokinase (Ape_0012) from , which displayed kinase activity toward a broad spectrum of substrates, including sugars, sugar phosphates, and nucleosides, and 36% identical to a phosphofructokinase from To examine the biochemical function of the Pcal_0041 protein, we cloned and expressed the gene and purified the recombinant protein. Although the Pcal_0041 protein contained a putative phosphofructokinase domain, it exhibited only low levels of phosphofructokinase activity.

Pcal_0632, a phosphorylating glyceraldehyde-3-phosphate dehydrogenase from Pyrobaculum calidifontis.

Genome sequence of the hyperthermophilic archaeon Pyrobaculum calidifontis contains an open reading frame, Pcal_0632, annotated as glyceraldehyde-3-phosphate dehydrogenase, which is partially overlapped with phosphoglycerate kinase. In the phylogenetic tree, Pcal_0632 clustered with phosphorylating glyceraldehyde-3-phosphate dehydrogenases characterized from hyperthermophilic archaea and exhibited highest identity of 54% with glyceraldehyde-3-phosphate dehydrogenase from Sulfolobus tokodaii. To examine biochemical function of the protein, Pcal_0632 gene was expressed in Escherichia coli and the gene product was purified.

Glutathione-Dependent Formaldehyde Dehydrogenase Homolog from Bacillus subtilis Strain R5 is a Propanol-Preferring Alcohol Dehydrogenase.

Genome search of Bacillus subtilis revealed the presence of an open reading frame annotated as glutathione-dependent formaldehyde dehydrogenase/alcohol dehydrogenase. The open reading frame consists of 1137 nucleotides corresponding to a polypeptide of 378 amino acids. To examine whether the encoded protein is glutathione-dependent formaldehyde dehydrogenase or alcohol dehydrogenase, we cloned and characterized the gene product.

Pcal_0111, a highly thermostable bifunctional fructose-1,6-bisphosphate aldolase/phosphatase from Pyrobaculum calidifontis.

Pyrobaculum calidifontis genome harbors an open reading frame Pcal_0111 annotated as fructose bisphosphate aldolase. Although the gene is annotated as fructose bisphosphate aldolase, it exhibits a high homology with previously reported fructose-1,6-bisphosphate aldolase/phosphatase from Thermoproteus neutrophilus. To examine the biochemical properties of Pcal_0111, we have cloned and expressed the gene in Escherichia coli.

Pcal_1127, a highly stable and efficient ribose-5-phosphate pyrophosphokinase from Pyrobaculum calidifontis.

Analysis of the genome sequence of Pyrobaculum calidifontis revealed the presence of an open reading frame Pcal_1127 annotated as ribose-5-phosphate pyrophosphokinase. To examine the properties of Pcal_1127 the coding gene was cloned, expressed in Escherichia coli, and the purified gene product was characterized. Pcal_1127 exhibited higher activity when ATP was replaced by dATP as pyrophosphate donor.