Congruent strategies for carbohydrate sequencing. 2. FragLib: an MSn spectral library

A bottom-up approach to achieve full oligosaccharide and glycan characterization has been described that is based on an MSn fragment spectral library and associated tools. The library, identified as FragLib, was initiated with known standards and commercially available oligomers prepared as methylated derivatives. As a component of this effort a set of software tools has been written for storing, organizing, and comparing spectral files, including the identification of isobaric mixtures. These tools provide a facile and objective evaluation of structural details including interresidue linkage, monomer identification, anomeric configuration, and branching. The tools are components of a web-based data sharing interface for sample tracking, spectral searching, and structural confirmation. Applications have been detailed with unknown samples and previously characterized glycoconjugates.