title: Structural assignment of disialylated biantennary N-glycan isomers derivatized with 2-aminopyridine using negative-ion multistage tandem mass spectral matching.
abstract: To investigate the possibility of structural assignment based on negative-ion multistage tandem mass (MS(n)) spectral matching, four isomers of disialylated biantennary N-glycans (alpha2-6 and/or alpha2-3 linked sialic acid on alpha1-6 and alpha1-3 antennae) derivatized with 2-aminopyridine (PA) were analyzed by employing high-performance liquid chromatography/electrospray ionization linear ion trap time-of-flight mass spectrometry (HPLC/ESI-LIT-TOFMS), which uses helium gas for ion trapping and collision-induced dissociation (CID). It is shown that the MS(2) spectra derived from each precursor ion [M-2H](2-) are reproducible and useful for distinguishing the four isomers. Thus, they can be assigned by negative-ion MS(2) spectral matching based on correlation coefficients. In addition, MS(3) spectra derived from D-type fragment ions clearly differentiate the alpha2-3- or alpha2-6-linked sialic acid on the alpha1-6 antenna due to their characteristic spectral patterns. The C(4)-type fragment ions, which are produced from both the alpha1-6 and alpha1-3 antennae, show the characteristic MS(3) spectra reflecting alpha2-3- or alpha2-6- linkage type or a mixture of both types. Thus, the differentiation and assignment of these disialylated biantennary N-glycan isomers can also be supported with the MS(3) spectra of C(4)- and D-type ions.
authors.affiliation: Graduate School of Advanced Life Science, Hokkaido University, Sapporo 001-0021, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ito
authors.forename: Kuriko
authors.initials: K
authors.lastname: Yamada
authors.forename: Kisaburo
authors.initials: K
authors.lastname: Deguchi
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nakagawa
authors.forename: Shin-Ichiro
authors.initials: S
authors.lastname: Nishimura
mesh_terms: D000631:Aminopyridines / Q000737:chemistry*; D000818:Animals; D002240:Carbohydrate Sequence; D002645:Chickens; D002851:Chromatography, High Pressure Liquid; D005260:Female; D007536:Isomerism; D008969:Molecular Sequence Data; D015394:Molecular Structure; D019158:N-Acetylneuraminic Acid / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry* / Q000145:classification; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000631:Aminopyridines; D011134:Polysaccharides; D019158:N-Acetylneuraminic Acid; C032439:alpha-aminopyridine