Determination of (1)H homonuclear scalar couplings in unlabeled carbohydrates.
The scarcity of structural information on carbohydrates results from combined difficulties to crystallize and the limitations in NMR analysis. Current methods for determining basic NMR parameters such as (1)H homonuclear scalar couplings are very limited, especially for large molecules such as polysaccharides, oligonucleotides, and the carbohydrate part of glycoproteins. In this paper, a NMR experiment for the determination of endocyclic (1)H homonuclear scalar couplings ((3)J(HH)) in unlabeled carbohydrates is presented. In addition to scalar couplings, cross-correlated dipole-dipole relaxation rates were measured for large polysaccharides. The measurement of all endocyclic homonuclear coupling constants within monosaccharide units is presented for lactose, a model disaccharide, and for a natural-abundance 2 MDa bacterial polysaccharide excreted by Streptococcus thermophilus Sfi39.
Zwahlen
Catherine
C
Université de Lausanne, Institut de Chimie Organique, CH-1015 Lausanne, Switzerland.
Vincent
Sébastien J F
SJ
D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry*; D007785:Lactose / Q000737:chemistry; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011135:Polysaccharides, Bacterial / Q000737:chemistry
D002241:Carbohydrates; D011135:Polysaccharides, Bacterial; C098632:exopolysaccharide, Streptococcus; D007785:Lactose