Scientific Publications by FDA Staff

J Am Soc Mass Spectrom 2007 Oct;18(10):1799-812

A glycomics platform for the analysis of permethylated oligosaccharide alditols.

Costello CE, Contado-Miller JM, Cipollo JF

Cipollo JF (reprint author), US FDA, Ctr Biol Evaluat & Res, Div Bacterial Parasit & Allergen Prod, 8800 Rockville Pike,Bldg 29A, Bethesda, MD 20892 USA US FDA, Ctr Biol Evaluat & Res, Div Bacterial Parasit & Allergen Prod, Bethesda, MD 20892 USA Boston Univ, Sch Med, Dept Biochem, Mass Spectrometry Resource, Boston, MA 02215 USA

This communication reports the development of an LC/MS platform for the analysis of permethylated oligosaccharide alditols that, for the first time, demonstrates routine online oligosaccharide isomer separation of these compounds before introduction into the mass spectrometer. The method leverages a high-resolution liquid chromatography system with the superior fragmentation pattern characteristics of permethylated oligosaccharide alditols that are dissociated under low-energy collision conditions using quadrupole orthogonal time-of-flight (QoTOF) instrumentation and up to pseudo MS(3) mass spectrometry. Glycoforms, including isomers, are readily identified and their structures assigned. The isomer-specific spectra include highly informative cross-ring and elimination fragments, branch position specific signatures, and glycosidic bond fragments, thus facilitating linkage, branch, and sequence assignment. The method is sensitive and can be applied using as little as 40 fmol of derivatized oligosaccharide. Because permethylation renders oligosaccharides nearly chemically equivalent in the mass spectrometer, the method is semiquantitative and, in this regard, is comparable to methods reported using high field NMR and capillary electrophoresis. In this postgenomic age, the importance of glycosylation in biological processes has become clear. The nature of many of the important questions in glycomics is such that sample material is often extremely limited, thus necessitating the development of highly sensitive methods for rigorous structural assignment of the oligosaccharides in complex mixtures. The glycomics platform presented here fulfills these criteria and should lead to more facile glycomics analyses.