open access

https://hdl.handle.net/2115/5844

Structural assignment of isomeric 2-aminopyridine derivatized monosialylated biantennary N-linked oligosaccharides using negative-ion MSn spectral matching

英語

2006

John Wiley & Sons

Rapid Communications in Mass Spectrometry

20(3)

412-418

To investigate the possibility of structural assignment based on negative-ion MSn spectral matching, four isomers of 2-aminopyridine-derivatized (PA) monosialylated oligosaccharides (i.e., complex type N-glycans with an α2-3 or α2-6 linked sialic acid on α1-6 or α1-3 antennae) were analyzed by using high-performance liquid chromatography/electrospray ion trap time-of-flight mass spectrometry(HPLC/ESI-IT-TOF MS). The negative ion [M-2H]2- is observed dominantly in the MS1 spectra without the loss of a sialic acid. The MS2 spectra derived from it are sufficiently reproducible that MS2 spectral matching based on correlation coefficients can be applied to the assignment of these isomers. The isomers containing a sialic acid on α1-6 or α1-3 antennae can be distinguished by MS2 spectral matching, but the α2-3 and α2-6 linkage types of sialic acid cannot be distinguished by their MS2 spectra. However, MS3 spectra derived from fragment ions containing a sialic acid (i.e., C4- and D-type ions) clearly differentiate the α2-3 and α2-6 linkage types of sialic acid in their MS3 spectral patterns. This difference might be rationalized in terms of a proton transfer from the reducing-end mannose to the negatively-charged sialic acid. These two moieties are very close in the structural conformations of the precursor C4-type fragment ions, as predicted by molecular mechanics calculations. Thus, negative-ion MSn (n=2, 3) spectral matching was proven to be useful for the structural assignment of these four monosialylated PA N-glycan isomers.

学術雑誌論文

Accepted Manuscript

Copyright © 2006 John Wiley & Sons, Inc., Rapid Communications in Mass Spectrometry, vol.20(3),p412-418

0951-4198