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 findings corroborate and rationalize the experimentally observed dioxidation of GLC by PDH and its promiscuity towards different sugars and suggest that the presence of the two potential catalytic bases His-512 and His-556 increases the versatility of the enzyme, by employing the most suitably oriented base depending on the substrate and its orientation in the active site.
Abstract: The flavin-dependent sugar oxidoreductase pyranose dehydrogenase (PDH) from the plant litter- degrading fungus Agaricus meleagris oxidizes D-glucose (GLC) efficiently at positions C2 and C3. The closely related pyranose 2-oxidase (P2O) from Trametes multi- color oxidizes GLC only at position C2. Consequently, the electron output per molecule GLC is twofold for PDH compared to P2O making it a promising catalyst for bio- electrochemistry or for introducing novel carbonyl func- tionalities into sugars. The aim of this study was to rationalize the mechanism of GLC dioxidation employing molecular dynamics simulations of GLC-PDH interac- tions. Shape complementarity through nonpolar van der Waals interactions was identified as the main driving force for GLC binding. Together with a very diverse hydrogen- bonding pattern, this has the potential to explain the experimentally observed promiscuity of PDH towards different sugars. Based on geometrical analysis, we pro- pose a similar reaction mechanism as in P2O involving a general base proton abstraction, stabilization of the tran- sition state, an alkoxide intermediate, through interaction with a protonated catalytic histidine followed by a hydride transfer to the flavin N5 atom. Our data suggest that the presence of the two potential catalytic bases His-512 and His-556 increases the versatility of the enzyme, by employing the most suitably oriented base depending on the substrate and its orientation in the active site. Our findings corroborate and rationalize the experimentally observed dioxidation of GLC by PDH and its promiscuity towards different sugars.
29 citations
TL;DR: The length of the fatty acid side chain in the ceramide portions greatly affects the immunostimulatory effects of α-galactosylceramides and α-GluCers and the configuration of the 4″-hydroxyl group of the inner pyranose moiety plays an important role in the Immunostimulation effects of monoglycosylated α- d -pyranosylcer amides.
29 citations
TL;DR: In this paper, the distributions of substituents in O -(2-hydroxyethyl) derivatives of starch and dextran have been examined by gas-liquid chromatography of the hydrolysates.
29 citations
TL;DR: In this paper, the tautomeric composition of a solution of ammonium 3-deoxy-d - manno -octulosonate (KDO, 1a ) in D 2 O at 28° was assessed by means of 13 C-F.m.t.-n.r.
29 citations
TL;DR: The quinone-dependent pyranose dehydrogenase purified from mycelial extracts of the basidiomycete fungus Agaricus meleagris catalyzed oxidation of the non-reducing oligosaccharides sucrose, melezitose and erlose at C-3 of their terminal glucopyranosyl moiety.
Abstract: The quinone-dependent pyranose dehydrogenase (PDH) purified from mycelial extracts of the basidiomycete fungus Agaricus meleagris catalyzed oxidation of the non-reducing oligosaccharides sucrose, melezitose and erlose at C-3 of their terminal glucopyranosyl moiety while α,α-trehalose was double oxidized at both C-3 and C-3′. Analogously, using MS and in situ NMR spectroscopy, formation of C-3 carbonyl derivatives was also demonstrated with methyl-α- d -Glcp, methyl-β- d -Glcp and methyl-α- d -Galp. Yields of conversions performed at room temperature with 10 mM sugars and 1,4-benzoquinone as an electron acceptor in non-buffered systems were ≥90% within 3–20 h, depending on substrate.
28 citations