angles of the glycosidic bond in polysaccharide and glycopeptide model compounds.
Our work greatly extends previous exploratory calculations performed on glycosidic
bond models carried out by Wilson and Webb, Mazeau, and others.9-11 We describe
the determination of
D-Glcp-D-Glcp model disaccharides in both the a and b configurations (Figure 1).
The calculations were done with the 3-21G basis set, and scaled to reference results
from 6-311G** level calculations. Similar surfaces were obtained for GlcNAc-1_Thr
and GlcNAc-1_Ser using different configurations for the peptide moiety, and results
obtained for both families of model compounds are compared. We also present the
determination of periodic formulae of the form d(13C) = _(f,y) obtained by fitting the
theoretical results to trigonometric series expansions suitable for use in molecular
modeling simulations.
Our investigations show the applicability of chemical shift surfaces to the study
of conformational preferences of polysaccharides and glycopeptides in cases
were other NMR data is unavailable.
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