title: Assignment Of Hexuronic Acid Stereochemistry In Synthetic Heparan Sulfate Tetrasaccharides With 2-O-Sulfo Uronic Acids Using Electron Detachment Dissociation.
abstract: The present work focuses on the assignment of uronic acid stereochemistry in heparan sulfate (HS) oligomers. The structural elucidation of HS glycosaminoglycans is the subject of considerable importance due to the biological and biomedical significance of this class of carbohydrates. They are highly heterogeneous due to their non-template biosynthesis. Advances in tandem mass spectrometry activation methods, particularly electron detachment dissociation (EDD), has led to the development of methods to assign sites of sulfo modification in glycosaminoglycan oligomers, but there are few reports of the assignment of uronic acid stereochemistry, necessary to distinguish glucuronic acid (GlcA) from iduronic acid (IdoA). Whereas preceding studies focused on uronic acid epimers with no sulfo modification, the current work extends the assignment of the hexuronic acid stereochemistry to 2-O-sulfo uronic acid epimeric tetrasaccharides. The presence of a 2-O-sulfo group on the central uronic acid was found to greatly influence the formation of B3, C2, Z2, and Y1ions in glucuronic acid and Y2and1,5X2for iduronic acid. The intensity of these peaks can be combined to yield a diagnostic ratios (DR), which can be used to confidently assign the uronic acid stereochemistry.
authors.affiliation: University of Georgia, Department of Chemistry, Athens, GA.
authors.forename: Isaac
authors.initials: I
authors.lastname: Agyekum
authors.affiliation: University of Georgia, Department of Chemistry, Athens, GA.
authors.forename: Anish B
authors.initials: AB
authors.lastname: Patel
authors.affiliation: University of Georgia, Complex Carbohydrate Research Center, Athens, GA, United States.
authors.forename: Chengli
authors.initials: C
authors.lastname: Zong
authors.affiliation: University of Georgia, Complex Carbohydrate Research Center, Athens, GA, United States.
authors.forename: Geert-Jan
authors.initials: GJ
authors.lastname: Boons
authors.affiliation: University of Georgia, Department of Chemistry, Athens, GA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Amster