GlyNest and CASPER

GlyNest and CASPER predict ^1H- and ^13C-NMR chemical shifts from glycan chemical structures to support structural determination of oligosaccharides and polysaccharides.

Key Features:

• Predictive capabilities: Both predict ^1H- and ^13C-NMR chemical shifts of glycans, with GlyNest encoding each atom's spherical environment and CASPER using an increment rule that adjusts shifts of free reducing monosaccharides based on attached residues.
• Performance and efficiency: Validation against a test set of 155 ^13C and 181 ^1H assigned spectra shows reduced standard deviations relative to methods not encoding stereochemistry, and computations run in the millisecond range on standard computers.
• Structural determination: CASPER accepts one-dimensional ^1H or ^13C spectra, two-dimensional C,H-correlation spectra, and component/linkage information to determine oligosaccharide and regular polysaccharide structures and to simulate spectra for multibranched oligo- and polysaccharides with reduced experimental signals.
• Integration with glycosciences resources: Both services integrate with the GLYCOSCIENCES.de portal and reference data sources including CarbBank, SugaBase, and 3D coordinates generated by SWEET-II.
• NMR assignment support: The methods enable automatic assignment of NMR spectra for identification and characterization of complex carbohydrates and support integration with genomics and proteomics data.

Scientific Applications:

• Oligosaccharide and polysaccharide structure elucidation: Determination of oligosaccharide and regular polysaccharide structures from experimental NMR data.
• High-throughput glycomics: Rapid prediction and annotation of glycan NMR spectra for large-scale glycomics projects.
• Integrative glycobiology studies: Combining NMR-based glycan assignments with genomics, proteomics, and carbohydrate database resources for comprehensive biological analyses.

Methodology:

GlyNest encodes each atom's spherical environment, while CASPER applies an increment rule adjusting free reducing monosaccharide shifts according to attached residues; CASPER processes one-dimensional ^1H or ^13C spectra, two-dimensional C,H-correlation spectra, and component/linkage information, can simulate spectra for multibranched oligo- and polysaccharides, and validation used a test set of 155 ^13C and 181 ^1H assigned spectra with reported standard deviations between experimental and estimated shifts; computations execute in the millisecond range.