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SUMMARY:Separation of Carbohydrate and Glycopeptide Isomers using Ion Mobi
 lity-Mass Spectrometry 
DTSTART:20151210T163000
DTEND:20151210T173000
DTSTAMP:20260916T011720Z
UID:a41e713c52069c6a468654111ebc2a0a20a98e67182c1777ecc60234
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Kevin Pagel\nFreie Universität Berlin\, Institute for C
 hemistry and Biochemistry and Fritz Haber Institute of the Max Planck Soci
 ety\, Berlin\, Germany\nComplex carbohydrates are of great importance for 
 a variety of biological functions. They can be linked to proteins as post-
 translational modifications or exist as free oligosaccharides\, for exampl
 e in milk. Currently\, the vast majority of complex carbohydrates are char
 acterized using mass spectrometry-based techniques (MS) that are directly 
 descending form those established in proteomics. Measuring the molecular w
 eight of a sugar\, however\, immediately poses a fundamental problem: enti
 re classes of the constituting monosaccharide building blocks exhibit an i
 dentical atomic composition and\, consequently\, also an identical mass. T
 herefore\, carbohydrate MS data can be highly ambiguous and often it is si
 mply not possible to clearly assign a particular molecular structure.\nA p
 romising approach to overcome the above-mentioned limitation is to impleme
 nt an additional gas phase separation step using ion mobility-mass spectro
 metry (IM MS). Here\, ions travel through a gas-filled cell aided by an el
 ectric field and are separated according to their mass\, charge\, size and
  shape. While the drift time of an ion depends on the underlying instrumen
 t conditions\, the collision cross section (CCS) is a molecular property t
 hat can be compared and calculated theoretically.\nHere\, we demonstrate t
 he potential of IM-MS to be used as a tool for the separation and identifi
 cation of isomeric carbohydrates and glycopeptides. First\, six synthetic 
 carbohydrate isomers that differ with respect to their composition\, conne
 ctivity\, or configuration were analyzed individually and as mixtures. Our
  data reveal that carbohydrate linkage- and stereoisomers\, which are diff
 icult to distinguish using established techniques such as liquid chromatog
 raphy or NMR\, can be separated and unambiguously identified on basis of t
 heir CCS. When mixed\, even minor isomeric components with relative concen
 trations as low as 0.1% were still clearly detectable.\nSecond\, we recent
 ly extended our investigations to glycopeptides. First preliminary data sh
 ow that the position of the carbohydrate within the peptide sequence can b
 e clearly identified using IM-MS when multiple glycosylation sites are pre
 sent. More importantly\, however\, our data reveal that also glycopeptides
 \, which merely differ in the regiochemistry of the attached carbohydrate\
 , can be distinguished using gas-phase fragmentation and subsequent IM-MS 
 analysis.\nThese results indicate that IM-MS is an exceptionally effective
  tool for the structural analysis of complex carbohydrates. The full benef
 it of this method will become apparent once CCS data of carbohydrates and 
 oligosaccharide fragments will be deposited in databases.
LOCATION:CH G1 495 https://plan.epfl.ch/?room==CH%20G1%20495
STATUS:CONFIRMED
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