Topic
Pyranose
About: Pyranose is a research topic. Over the lifetime, 1619 publications have been published within this topic receiving 35348 citations. The topic is also known as: pyranoses & hexopyranose.
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TL;DR: The heterologous expression of one of the pyranose dehydrogenase genes, encoding the major PDH protein in Agaricus meleagris, is reported here, for the first time, in the filamentous fungi Aspergillus nidulans, and AsperGillus niger.
Abstract: Pyranose dehydrogenase (PDH) is a flavin-dependant sugar oxidoreductase found in the family Agaricaceae, basidiomycetes that degrade lignocellulose-rich forest litter, and is catalytically related to the fungal enzymes pyranose 2-oxidase and cellobiose dehydrogenase. It has broad substrate specificity and displays similar activities with most sugar constituents of lignocellulose including disaccharides and oligosaccharides, a number of (substituted) quinones, and metal ions are suitable electron acceptors rather than molecular oxygen. In contrast to pyranose 2-oxidase and cellobiose dehydrogenase, which oxidize regioselectively at C-2 and C-1, respectively, PDH is capable of oxidation on C-1 to C-4 as well as double oxidations, depending on the nature of the substrate. This makes it a very interesting enzyme for biocatalytic applications, as many of the reaction products are otherwise unaccessible by chemical or enzymatic means. PDH was characterized in detail in a limited number of fungi, and the first encoding genes were isolated only recently. We report here, for the first time, the heterologous expression of one of these genes, encoding the major PDH protein in Agaricus meleagris, in the filamentous fungi Aspergillus nidulans, and Aspergillus niger.
18 citations
TL;DR: X-ray crystallographic analysis was performed on the compound to which had been assigned the structure of 1,2,3,4-tetra-O -acetyl-5,6-dideoxy-6-C -nitro-5-(phenylphosphinyl)- d -glucopyranose.
18 citations
TL;DR: In this article, the up-conversion of wild type pyranose 2-oxidase (P2O) was investigated in solution by means of fluorescence upconversion method, and the (τ2/τ1) ratio (∼3200) was extraordinary high compared to other flavoproteins without subunit structure.
Abstract: Ultrafast fluorescence dynamics of flavin adenine dinucleotide (FAD) in wild type pyranose 2-oxidase (P2O) has been investigated in solution by means of fluorescence up-conversion method. Fluorescence decays were well described by two-exponential model function. Fluorescence lifetimes were τ1 ∼ 110 fs and τ2 ∼ 360 ps, respectively. The (τ2/τ1) ratio (∼3200) was extraordinary high compared to other flavoproteins without subunit structure. The heterogeneous distribution of emission lifetimes were elucidated in terms of two different conformers of P2O; conformer 1 with τ1 and conformer 2 with τ2. Emission peaks of conformer 1 and conformer 2 were determined to be at ∼540 nm and 510 nm, respectively, using transient spectral reconstruction procedure. Using dynamics analysis by Kakitani and Mataga (KM) theory, both quenching processes were ascribed to photoinduced electron transfer (ET) reactions mainly from Trp168 to the excited isoalloxazine (Iso*) in different protein tetramers having different static dielectric constants (ɛ1 ∼ 3.25 for conformer 1 and ɛ2 ∼ 5.93 for conformer 2). The quaternary structure seems to be responsible for the observed conformational heterogeneity.
18 citations
TL;DR: The addition of the phosphonate-sulphone to the carbohydrates gave the tetrehydropyrans as mixtures of α- and β-isomers as discussed by the authors.
Abstract: The addition of the phosphonate–sulphone (8) to the carbohydrates (9) and (10) gave the tetrehydropyrans (11) and (12) as mixtures of α- and β-isomers; treatment of the mixture with sodium hydride gave the purer β-isomers
18 citations
TL;DR: In this paper, a stereocontrolled route to (1→6)-hydroxymethylene-linked C-disaccharide derivatives has been developed based on cycloaddition of pyranose 1-carbonitrile oxides to 5,6-dideoxyhex-5enofuranoses and reductive hydrolytic cleavage of the resulting 2-isoxazolines.
18 citations