N -Glycopedia: Libraries for Native N -glycan Structural Analysis

Studies on glycans of glycoproteins are hampered by the lack of standards that reflect the wide diversity in structure typically observed. To this end we have exploited a large library of N -glycan standards comprised of a unique collection of 226 N -glycans including oligomannose, hybrid, and complex-type. We generated a method employing porous graphitized carbon (PGC) and liquid chromatography mass spectrometry (PGC-LC-MS), which can provide a high degree of resolution of underivatized N -glycan structures. Chromatogram libraries arising from these studies include retention time data, diagnostic fragments, and validated structural assignments, providing a robust platform for both targeted and discovery-based glycomics. We refer to this as an N -glycopedia, the first type of resource in which researchers can compare this collective data to N -glycans under study and overcome the limitations of only having compositional data and predicted structures. The technology is easily expandable to include additional N -glycans as new standards become available.