Identification of isomeric N-glycan structures by mass spectrometry with 157 nm laser-induced photofragmentation.
Characterization of structural isomers has become increasingly important and extremely challenging in glycobiology. This communication demonstrates the capability of ion-trap mass spectrometry in conjunction with 157 nm photofragmentation to identify different structural isomers of permethylated N-glycans derived from ovalbumin without chromatographic separation. The results are compared with collision-induced dissociation (CID) experiments. Photodissociation generates extensive cross-ring fragment ions as well as diagnostic glycosidic product ions that are not usually observed in CID MS/MS experiments. The detection of these product ions aids in characterizing indigenous glycan isomers. The ion trap facilitates MS(n) experiments on the diagnostic glycosidic fragments and cross-ring product ions generated through photofragmentation, thus allowing unambiguous assignment of all of the isomeric structures associated with the model glycoprotein used in this study. Photofragmentation is demonstrated to be a powerful technique for the structural characterization of glycans.
Devakumar
Arugadoss
A
Department of Chemistry, Indiana University, Bloomington, Indiana 47405-4001, USA.
Mechref
Yehia
Y
Kang
Pilsoo
P
Novotny
Milos V
MV
Reilly
James P
JP
D000818:Animals; D007536:Isomerism; D007834:Lasers; D010047:Ovalbumin / Q000737:chemistry; D010777:Photochemistry; D011134:Polysaccharides / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods*
D011134:Polysaccharides; D010047:Ovalbumin