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Complete ¹H and ¹³C NMR chemical shift assignments of mono-, di-, and trisaccharides as basis for NMR chemical shift predictions of polysaccharides using the computer program casper
- Roslund, Mattias U., Säwén, Elin, Landström, Jens, Rönnols, Jerk, Jonsson, K.Hanna M., Lundborg, Magnus, Svensson, Mona V., Widmalm, Göran
- Carbohydrate research 2011 v.346 no.11 pp. 1311-1319
- Klebsiella, Salmonella enterica subsp. arizonae, Shigella flexneri, computer software, data collection, lipopolysaccharides, nuclear magnetic resonance spectroscopy, prediction, protons, reducing sugars, serotypes, trisaccharides
- The computer program casper uses ¹H and ¹³C NMR chemical shift data of mono- to trisaccharides for the prediction of chemical shifts of oligo- and polysaccharides. In order to improve the quality of these predictions the ¹H and ¹³C, as well as ³¹P when applicable, NMR chemical shifts of 30 mono-, di-, and trisaccharides were assigned. The reducing sugars gave two distinct sets of NMR resonances due to the α- and β-anomeric forms. In total 35 ¹H and ¹³C NMR chemical shift data sets were obtained from the oligosaccharides. One- and two-dimensional NMR experiments were used for the chemical shift assignments and special techniques were employed in some cases such as 2D ¹H,¹³C-HSQC Hadamard Transform methodology which was acquired approximately 45 times faster than a regular t₁ incremented ¹H,¹³C-HSQC experiment and a 1D ¹H,¹H-CSSF-TOCSY experiment which was able to distinguish spin-systems in which the target protons were only 3.3Hz apart. The ¹H NMR chemical shifts were subsequently refined using total line-shape analysis with the PERCH NMR software. The acquired NMR data were then utilized in the casper program (http://www.casper.organ.su.se/casper/) for NMR chemical shift predictions of the O-antigen polysaccharides from Klebsiella O5, Shigella flexneri serotype X, and Salmonella arizonae O62. The data were compared to experimental data of the polysaccharides from the two former strains and the lipopolysaccharide of the latter strain showing excellent agreement between predicted and experimental ¹H and ¹³C NMR chemical shifts.