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. Author manuscript; available in PMC: 2012 Dec 20.
Published in final edited form as: Biochemistry. 2011 Nov 28;50(50):10941–10950. doi: 10.1021/bi201450v

Figure 4. Multi-stage tandem MS reveals the structural linkage for [4,2,2][0,0,0].

Figure 4

Tandem MS of the saccharide [4,2,2][0,0,0], [M + 2Na]2+ m/z 824.2961, and its product ions was performed on an LTQ-Oribtrap XL mass spectrometer in positive ion mode. CID fragmentations of the precursor ion m/z 824.2961 (A), MS3 of the ion at m/z 833.3009 (B), and MS4 of the ions at m/z 646.2158 (C) and 660.2314 (D) are displayed on the chemical structures as glycosidic bond cleavages labeled in blue, cross-ring cleavages in red, and internal cleavages in green. Monosaccharide residues abbreviations QM (Qui4NFm), GN (GalNAcAN), and QC (QuiNAc) are shown inside the six-member rings for clarity. One pair of internal cleavage is shown in purple to represent the alternative assignments. All fragments contain Na.