Determination of sulfation pattern in brain glycosaminoglycans by chip-based electrospray ionization ion trap mass spectrometry

• Published in: Analytical & bioanalytical chemistry (Print) 2009-12, Vol.395 (8), p.2489-2498
• Main Authors: Flangea, Corina, Schiopu, Catalin, Sisu, Eugen, Serb, Alina, Przybylski, Michael, Seidler, Daniela G, Zamfir, Alina D
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Animals; Biochemistry; Brain; Brain - metabolism; Chains; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Chondroitin Sulfates - analysis; Dermatan Sulfate - analysis; Disaccharides - analysis; Exact sciences and technology; Food Science; Glycosaminoglycans; Glycosaminoglycans - chemistry; Glycosaminoglycans - metabolism; Ionization; Laboratory Medicine; Mice; Mice, Inbred C57BL; Monitoring/Environmental Analysis; Nanomaterials; Nanostructure; Nanotechnology; Original Paper; Spectrometric and optical methods; Spectrometry, Mass, Electrospray Ionization - methods; Sulfates; Sulfates - analysis; Sulfation
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-009-3167-0

Chondroitin sulfate (CS) and dermatan sulfate (DS) glycosaminoglycans display variability of sulfation in their constituent disaccharide repeats during chain elongation. Since a large proportion of the extracellular matrix of the central nervous system (CNS) is composed of proteoglycans, CS/DS disaccharide degree and profile of sulfation play important roles in the functional diversity of neurons, brain development, and some of its pathological states. To investigate the sulfation pattern of CS/DS structures expressed in CNS, we introduced here a novel method based on an advanced system encompassing fully automated chip nanoelectrospray ionization (nanoESI) in the negative ion mode and high capacity ion trap multistage mass spectrometry (MS²-MS³) by collision-induced dissociation (CID). This method, introduced here for the first time in glycomics of brain glycosaminoglycans, was particularly applied to structural investigation of disaccharides obtained by β-elimination and digestion with chondroitin B and AC I lyase of hybrid CS/DS chains from wild-type mouse brain. Screening in the chip-MS mode of DS disaccharide fraction resulting after depolymerization with chondroitin B lyase revealed molecular ions assigned to monosulfated disaccharide species having a composition of 4,5-Δ-[IdoA-GalNAc]. By optimized CID MS²-MS³, fragment ions supporting the localization of sulfate ester group at C4 within GalNAc were produced. Chip ESI MS profiling of CS disaccharide fraction obtained by depolymerization of the same CS/DS chain using chondroitin AC I lyase indicated the occurrence of mono- and bisulfated 4,5-Δ-[GlcA-GalNAc]. The site of oversulfation was determined by MS²-MS³, which provided sequence patterns consistent with a rare GlcA-3-sulfate-GalNAc-6-sulfate structural motif. [graphic removed]