C. Landersjo et al., NMR investigation of a tetrasaccharide using residual dipolar couplings indilute liquid crystalline media: Effect of the environment, J PHYS CH B, 104(23), 2000, pp. 5618-5624
The tetrasaccharide lacto-N-neotetraose, beta-D-Galp-(1-->4)-beta-D-GlcpNAc
-(1-->3)-beta-D-Galp-(1-->4)-D-Glcp, was investigated by measurements of re
sidual dipolar couplings in two lyotropic liquid crystalline media: (i) pre
pared from mixtures of dimyristoyl phosphatidylcholine and dihexanoyl phosp
hatidylcholine in water, and (ii) a ternary system consisting of cetylpyrid
inium chloride/n-hexanol/brine (200 mM NaCl in water). Computer simulations
, both Monte Carlo and molecular dynamics, were performed where different f
orce fields were employed. The molecular structures generated were used in
the analysis of the experimental dipolar C-H couplings. This analysis indic
ated that in addition to different orientational tensors, a small conformat
ional difference may be present for the oligosaccharide in the two media. T
his interpretation emerged from a procedure where the effect of rotation ar
ound one central glycosidic torsion angle on dipolar couplings was investig
ated. Thus, the approach based on measurement of dipolar couplings is a sen
sitive tool for investigation of molecular conformation.