Solution conformation of various uridine diphosphoglucose salts as probed by NMR spectroscopy.
The solution conformations of uridine diphosphoglucose (UDP-Glc) under a variety of conditions (solvent, ionic strength, various mono- and divalent cations) have been studied by NMR spectroscopy (1H, 13C, 31P, and 25Mg). In the case of divalent cations (Ca2+, Mg2+, Mn2+) the phosphate oxygens are the preferred coordination sites and analysis of the 25Mg linewidths of solutions with various [Mg2+]/[UDP-Glc] ratios, indicates that the 1:1 Mg2+ UDP-Glc complex is the major species. From 13C relaxation data and hydrodynamic theory, it has been demonstrated that under all conditions UDP-Glc adopts a fairly extended overall shape and that magnesium ions lead to a significant increase in the average length of the UDP-Glc molecule as compared to monovalent cations. Thus, one of the roles of the metal ion in enzymic reactions involving nucleotide sugars may be to preorganize the nucleotide sugar.
Monteiro
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Centre de Recherches sur les Macromolécules Végétales, CNRS (associated with University Joseph Fourier), Grenoble, France.
Neyret
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Leforestier
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Hervé du Penhoat
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D001665:Binding Sites; D002236:Carbohydrate Conformation / Q000187:drug effects; D002413:Cations, Divalent / Q000494:pharmacology; D002414:Cations, Monovalent / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007554:Isotopes; D008274:Magnesium / Q000494:pharmacology; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D009994:Osmolar Concentration; D012492:Salts; D012996:Solutions; D012997:Solvents / Q000494:pharmacology; D014532:Uridine Diphosphate Glucose / Q000737:chemistry*
D002413:Cations, Divalent; D002414:Cations, Monovalent; D007554:Isotopes; D012492:Salts; D012996:Solutions; D012997:Solvents; D008274:Magnesium; D014532:Uridine Diphosphate Glucose