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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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Journal ArticleDOI
TL;DR: Steady‐state kinetics indicated that Gln392, Tyr510, Val511 and His556 are important for the catalytic efficiency of PDH, and molecular dynamics simulations and free energy calculations suggest that van der Waals interactions are the main driving force for substrate recognition and binding.
Abstract: Monomeric Agaricus meleagris pyranose dehydrogenase (AmPDH) belongs to the glucose-methanol-choline family of oxidoreductases. An FAD cofactor is covalently tethered to His103 of the enzyme. AmPDH can double oxidize various mono- and oligosaccharides at different positions (C1 to C4). To study the structure/function relationship of selected active-site residues of AmPDH pertaining to substrate (carbohydrate) turnover in more detail, several active-site variants were generated, heterologously expressed in Pichia pastoris, and characterized by biochemical, biophysical and computational means. The crystal structure of AmPDH shows two active-site histidines, both of which could take on the role as the catalytic base in the reductive half-reaction. Steady-state kinetics revealed that His512 is the only catalytic base because H512A showed a reduction in (kcat /KM )glucose by a factor of 10(5) , whereas this catalytic efficiency was reduced by two or three orders of magnitude for His556 variants (H556A, H556N). This was further corroborated by transient-state kinetics, where a comparable decrease in the reductive rate constant was observed for H556A, whereas the rate constant for the oxidative half-reaction (using benzoquinone as substrate) was increased for H556A compared to recombinant wild-type AmPDH. Steady-state kinetics furthermore indicated that Gln392, Tyr510, Val511 and His556 are important for the catalytic efficiency of PDH. Molecular dynamics (MD) simulations and free energy calculations were used to predict d-glucose oxidation sites, which were validated by GC-MS measurements. These simulations also suggest that van der Waals interactions are the main driving force for substrate recognition and binding.

16 citations

Journal ArticleDOI
TL;DR: The orientational preferences of the aldehyde or ketone groups are correlated with the relative populations of anomers characteristic of cyclic aldo- and ketohexoses, respectively, thus indicating that basic features of anomeric equilibria are preserved even if hexose molecules are not in their cyclic forms.
Abstract: The molecular properties of aldohexoses and ketohexoses are usually studied in the context of their cyclic, furanose or pyranose structures which is due to the abundance of related tautomeric forms in aqueous solution. We studied the conformational features of a complete series of D-aldohexoses (D-allose, D-altrose, D-glucose, D-mannose, D-gulose, d-idose, D-galactose and D-talose) and D-ketohexoses (D-psicose, D-fructose, D-sorbose and D-tagatose) as well as of L-psicose by using microsecond-timescale molecular dynamics in explicit water and DMSO with the use of enhanced sampling methods. In each of the studied cases the preferred conformation corresponded to an extended chain structure; the less populated conformers included the quasi-cyclic structures, close to furanose rings and common for both aldo- and ketohexoses. The orientational preferences of the aldehyde or ketone groups are correlated with the relative populations of anomers characteristic of cyclic aldo- and ketohexoses, respectively, thus indicating that basic features of anomeric equilibria are preserved even if hexose molecules are not in their cyclic forms. No analogous relationship is observed in the case of other structural characteristics, such as the preferences of acyclic molecules to form either the furanose-or pyranose-like structures or maintaining the chair-like geometry of pseudo-pyranose rings.

16 citations

Journal ArticleDOI
TL;DR: The first facile and efficient route to pyranose-fused butenolides from furanose scaffolds, convenient for scaling up production, is described.

16 citations

Journal ArticleDOI
TL;DR: In this paper, the reaction of methyl 2,3-anhydro-4,6-O-benzylidene-α-d -allopyranoside (3 ) with Ph n MLi [M = As or P, n = 2; M = Sn, n= 3] gives methyl 4,6O-bene-2,deoxy-2-M-α -d -altropyraniumide (4 ; M = Ph 2 As, Ph 2 P or Ph 3 Sn).

16 citations

Journal ArticleDOI
TL;DR: 2-Azido- 4-benzylamino-4-N-,3-O-carbonyl-2,4,6-trideoxy-d-galactopyranosyl trichloroacetimidate (14) was conveniently prepared by regioselective introduction of an N-benzyl carbamate at O-3 of 6-deoxy- d-glucal 6, followed by mesylation atO-4.

16 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202317
202228
202118
202027
201926
201819