为获得系列α-1,2-葡聚寡糖,首先以蓝藻寡糖六糖、八糖、九糖和十糖为原料,在0.5 mol/L的三氟乙酸( TFA)中于95℃酸解9 min以脱去还原端果糖,经低压凝胶色谱分离纯化,用电喷雾离子化-碰撞诱导解离-串联质谱(ESI-CID-MS/MS)和基质辅助激光解吸电离质谱(MALDI-MS)鉴定和序列表征,获得了除去末端果糖的α-1,2-五、七、八和九糖;然后在0.5 mol/L的TFA中于95℃对混合蓝藻寡糖六糖和八糖酸水解45 min,用Bio-Gel P2凝胶柱对混合物进行分离和纯化,并通过ESI-MS和MALDI-MS对获得的每个寡糖组份进行表征,获得了聚合度为2,3,4和6的α-1,2-葡聚寡糖.本研究为利用糖生物芯片技术进行α-1,2-葡聚寡糖的功能筛选及分析其与靶标蛋白之间相互作用的特异性提供了葡聚寡糖物质基础.
Carbohydrate microarray has become a powerful tool to explore the structure-function relationship between protein-carbohydrate, but it depends on enough reducing terminal oligosaccharides with aldehyde group. Nostoc oligosaccharides are a kind of oligo(1→2)-α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside. To acquire a full series of α-1,2-gluco-oligosaccharides from oligo(1→2)-α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside, the terminal fructose of four Nostoc oligosaccharides were removed using acid hydrolysis methods under the condition of 0. 5 mol/L trifluoroacetic acid( TFA) treated at 95 ℃ for 9 min, respectively. Following hydrolyzed products were separated and purified using high performance liquid chromatography ( HPLC) , and then electrospray ionization-collision-induce dissociation tandem mass spectrometry ( ESI-CID-MS/MS) and matrix assisted laser desorption ionization(MALDI)-MS were used to identify the removing of terminal fructose and sequenced, α-1,2-Glc5, Glc7, Glc8 and Glc9 were acquired. The mixture of Nostoc-Octa and Nostoc-Hexa treated with 0. 5 mol/L TFA at 95 ℃ for 45 min were used to acquire low degree of polymerization(DP) of α-1,2-gluco-oligosaccharides, which were separated with P2 column, ESI-MS and MALDI-MS were used to analysis these oligosaccharides, α-1,2-gluco-oligosaccharides with the degree of polymerization 2, 3, 4 and 6 were obtained. Finally, full series ofα-1-2-gluco-oligosaccharides from 2 mer to 9 mer were acquired successfully.