Building Up Key Segments of N-Glycans in the Gas Phase: Intrinsic Structural Preferences of the alpha(1,3) and alpha(1,6) Dimannosides

摘要

The intrinsic conformer specific vibrational spectra of two important subunits of the core pentasaccharide of N-linked glycans,the alpha (1,3) and alpha (1,6) dimannosides,have been recorded in the gas phase.Coupling these measurements with a computational exploration of their conformational landscapes has enabled their conformational assignment and has identified characteristic vibrational signatures associated with particular conformational families-including those that do or do not display inter-ring hydrogen bonding across the glycosidic linkage.In addition,the IR spectra of the monosaccharide moieties provide benchmarks,through which the conformational assignments can be refined.This introduces a general concept of modularity and secondary structure in oligosaccharides-essential for the success of similar studies on larger oligosaccharides in the future.