Oxidation and metal-ion affinities of a novel cyclic tetrasaccharide.
The cyclic tetrasaccharide, cyclo-(-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->), was oxidized in high yield to a dicarboxylic acid, cyclo-(-->6)-alpha-D-Glcp-(1-->3)-alpha-D-GlcpA-(1-->6)-alpha-D-Glcp-(1-->3)-alpha-D-GlcpA-(1-->). The parent and oxidized compound were then screened for the ability to form stable complexes with 20 metal cations. Ion-exchange thin-layer chromatography was utilized to survey binding in aqueous and 50% methanolic solutions. The screening identified Pb2+, Fe2+ and Fe3+ as forming strong metal chelates with the oxidized cyclic tetrasaccharide. The stoichiometry of the oxidized cyclic tetrasaccharide and Pb2+ complex was determined to be 1:1 using aqueous gel-permeation chromatography. Perturbations between the free and complexed structure were examined using NMR spectroscopy. Molecular simulations were used to identify a probable structure of oxidized cyclic tetrasaccharide complexed with Pb2+.
Dunlap
Christopher A
CA
Fermentation Biotechnology Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, United States Department of Agriculture, 1815 North University Street, Peoria, IL 61604-3999, USA. dunlapc@ncaur.usda.gov
Côté
Gregory L
GL
Momany
Frank A
FA
D002384:Catalysis; D002855:Chromatography, Thin Layer; D003497:Cyclic N-Oxides; D007477:Ions / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D007854:Lead / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D015394:Molecular Structure; D009844:Oligosaccharides / Q000737:chemistry*; D010084:Oxidation-Reduction
D003497:Cyclic N-Oxides; D007477:Ions; D009844:Oligosaccharides; D007854:Lead; D007501:Iron; C003959:TEMPO