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Download fileEstimating Collision Cross Sections of Negatively Charged N-Glycans using Traveling Wave Ion Mobility-Mass Spectrometry
journal contribution
posted on 2014-11-04, 00:00 authored by Johanna Hofmann, Weston
B. Struwe, Charlotte A. Scarff, James H. Scrivens, David
J. Harvey, Kevin PagelGlycosylation is one of the most
common post-translational modifications
occurring in proteins. A detailed structural characterization of the
involved carbohydrates, however, is still one of the greatest challenges
in modern glycoproteomics, since multiple regio- and stereoisomers
with an identical monosaccharide composition may exist. Recently,
ion mobility-mass spectrometry (IM-MS), a technique in which ions
are separated according to their mass, charge, and shape, has evolved
as a promising technique for the separation and structural analysis
of complex carbohydrates. This growing interest is based on the fact
that the measured drift times can be converted into collision cross
sections (CCSs), which can be compared, implemented into databases,
and used as additional search criteria for structural identification.
However, most of the currently used commercial IM-MS instruments utilize
a nonuniform traveling wave field to propel the ions through the IM
cell. As a result, CCS measurements cannot be performed directly and
require calibration. Here, we present a calibration data set consisting
of over 500 reference CCSs for negatively charged N-glycans and their fragments. Moreover, we show that dextran, already
widely used as a calibrant in high performance liquid chromatography,
is also a suitable calibrant for CCS estimations. Our data also indicate
that a considerably increased error has to be taken into account when
reference CCSs acquired in a different drift gas are used for calibration.