Synthesis, NMR spectroscopy and conformational studies of the four anomeric methyl glycosides of the trisaccharide D-Glcp-(1→3)-[D-Glcp-(1→4)]-α-D-Glcp

Abstract

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

NMR analysis of the O‐antigen polysaccharide from Escherichia coli strain F171

“…Closer inspection of the substitution patterns at C-3 and C-4 is in complete agreement with those of model substances in which twoˇ-linked D-Glc residues substituting these positions lead to small effects. 7 This is also the case for the E. coli strain F171 O-antigen polysaccharide where thę -L-Hexp residue (A) substituting position 3 has a similar stereochemistry at the glycosidic linkage to aˇ-D-Hexp residue (model substance).…”

Application of NMR, molecular simulation, and hydrodynamics to conformational analysis of trisaccharides

“…26 The 1 H and 13 C chemical shifts obtained agree with published values. 16,17 Adaptation of this experiment to include a 13 C inversionrecovery 27 component immediately preceding the constanttime evolution period ( Figure 2) was used to measure 13 C spin-lattice (T 1 ) relaxation times. Ten relaxation delays (denoted t in Figure 2) ranging from 10 ms to 5 s were used for both I and II.…”

“…16,17 All samples were prepared in 100% deuterium oxide (D 2 O) obtained from Sigma (St. Louis, MO). NMR samples of I and II contained 33 and 29 mM trisaccharide, respectively.…”

“…These trisaccharides exhibit vicinal substitution, a linkage pattern that may result in complex dynamic behavior as indicated by recent Metropolis Monte Carlo simulations. 16 A combination of experiment and theory was applied. Such an approach is necessary because the experimental NMR methods typically require models for interpretation, and the models generated with current computer simulations require experimental verification.…”

Structural studies and biosynthetic aspects of the O-antigen polysaccharide from Escherichia coli O174

“…The substitution positions for the sugar residues were identified from 13 C NMR glycosylation shifts; 36 Additionally, the 1 H, 31 P-hetero-TOCSY spectrum with a mixing time of 54 ms (Fig. 4b) allowed tracing of the full proton spin system of the glycerol residue (H1 to H3 in residue E) and the protons H1 to H5 in the spin system of residue D.…”