【作者】 王玉峰；

【导师】 于广利；

【作者基本信息】 中国海洋大学 ， 药物化学， 2011， 博士

【摘要】 本论文以红藻来源的半乳聚糖,κ-,τ-,λ-卡拉胶、琼胶、硫琼胶以及化学处理得到的脱硫κ-,λ-卡拉胶为原料,采用弱酸降解制备各种寡糖混合物,通过低压凝胶渗透色谱（Low pressure gel permeation chromatography, LPGPC）技术获得各系列寡糖单体37个,其中9个为首次获得。通过电喷雾离子化质谱（Electrospray ionization mass chromatography, ESI-MS）方法对所得寡糖结构和序列进行了确证。以制备的半乳寡糖为原料,通过还原胺化法将其与具有氨基的磷脂（DHPE）偶联,制备了40个拟半乳寡糖脂,其中14个为首次获得。以制备的拟糖脂为原料,考察了四种构建糖芯片的方法,即薄层点样仪制备微型糖芯片、手动点样仪制备微型糖芯片、薄层点样仪制备min-糖芯片和全自动芯片点样仪制备高密度糖芯片的优缺点。结果表明,mini-糖芯片适合于海洋糖芯片的构建,而微型芯片适用于糖与蛋白结合实验的条件摸索。利用mini-糖芯片技术和ELISA实验方法对各半乳寡糖与RCA₁₂₀结合,首次研究发现RCA₁₂₀特异性识别非还原端为Galβ1,4anGal结构的寡糖,进一步研究还发现:（1）非还原端Gal的C-2或C-6位被硫酸基取代后,可增强其与RCA₁₂₀的亲和力;（2）非还原端Gal的C-4位被硫酸基取代后,会失去与RCA₁₂₀的亲和力,除去C-4位硫酸基后亲和力将显著升高;（3）非还原端Gal的C-3位被α-Gal取代后,对RCA₁₂₀亲和力无影响,但被α-L-anGal取代后,将完全失去与RCA₁₂₀结合能力。各半乳寡糖与RCA₁₂₀的亲和力顺序为:Gal6Sβ1,4anGal（L）-R > Gal2Sβ1,4Gal2S6S-R > Galβ1,4anGal（L）-R > Galβ1,4GlcNAc-R > Galβ1,4anGal（D）-R > Galβ1,4Gal-R≈Galα1,3Galβ1,4Gal-R > Gal4Sβ1,4anGal（D）-R≈Galβ1,3GlcNAc-R≈Neu5Acα2,6Galβ1,4GlcNAc-R≈anGal（L）α1,3Gal6Sβ1,4anGal（L）-R （R代表单糖或寡糖）。ECL特异性识别含有乳糖胺（Galβ1,4GlcNAc-R）结构单元,非还原端Gal羟基被任何其它基团取代后,都影响其亲和力,但非还原端为Galβ1,4anGal（L or D）结构的寡糖与ECL有微弱的结合力。此外,利用构建的mini-糖芯片技术还研究了30种半乳寡糖与Galectin-3的亲和力差异。结果表明:Galectin-3除了识别常规Galβ1,4GlcNAc结构外,与琼胶七糖以上寡糖（Galβ1,4anGal（L）-R）以及三至五糖的硫琼胶寡糖（Gal6Sβ1,4anGal（L）-R）有较强的亲和力。该结果为硫琼胶寡糖作为Galectin-3抑制剂,用于新型抗肿瘤药物的开发提供了基础。更多还原

【Abstract】 In this thesis, seven series of marine galactan-derived oligosaccharides were obtained fromκ-,τ-,λ-carrageenan, agarose, sulfated agarose,desulfatedκ-,λ-carrageenan by mild acid hydrolysis and low pressure gel permeation chromatography （LPGPC）. The sequence of the thirty seven oligosaccharides were determined by electrospray ionization mass chromatography （ESI-MS）, in which nine oligosaccharides were firstly reported. Then, all galactan oligosaccharides were covalently linked to 1,2-dihexadecyl-sn- glycero-3-phospho-ethanolamine （DHPE） to acquire neoglycolipids by a reductive animation reaction. Forty neoglycolipids （NGLs） were prepared, and forteen NGLs were firstly reported.Four methods of preparing glycochip, including micro-glycochip by automatic TLC sampler, micro-glycochip by 8-pin hand-held micoarrayer, mini-glycochip by automatic TLC sampler and glycochip by high-density microarrayer were established. Mini-glycochip was fit for establishing marine glycan chip, while micro-glycochip was fit for optimizing the content of oligosaccharides probes and lectins. Specificity of RCA₁₂₀ and galactan oligosaccharides was estimated by min-glycan chip and ELISA. We firstly found that RCA₁₂₀ can strongly bind to the oligosaccharides who have the sturcture of Galβ1,4anGal-R, and we further confirmed that: 1) the binding ability to RCA₁₂₀ was significantly strengthen by adding a sulfate group at the 6-O- or 2-O-position of non-reducing end galactose; 2) the binding ability to RCA₁₂₀ was abolished by the addition of a sulfate group at the 4-O-position of non-reducing end galactose; 3) the binding ability to RCA₁₂₀ wasn’t affected by substitution ofα-D-Gal at the 3-O-position of non-reducing end galactose, but can be interrupted by adding α-L-anGal. The binding ability of galactan oligosaccharides with RCA₁₂₀ was as following: Gal6Sβ1,4anGal（L）-R > Gal2Sβ1,4Gal2S6S-R > Galβ1,4anGal（L）-R > Galβ1,4GlcNAc-R > Galβ1,4anGal（D）-R > Galβ1,4Gal-R≈Galα1,3Galβ1,4Gal-R > Gal4Sβ1,4anGal（D）-R≈Galβ1,3GlcNAc-R≈Neu5Acα2,6Galβ1,4GlcNAc-R≈anGal（L）α1,3Gal6Sβ1,4anGal（L）-R （R stands for monosaccharide or oligosaccharides）. ECL strongly bound to Galβ1,4GlcNAc structure, but displayed weak affinity with other sulfated oligosaccharides such asκ-,ι-,λ-carrageenan oligosaccharides. ECL only showed weak affinity to Galβ1,4anGal（L or D） structure.Furthermore, the affinity differences of thirty marine galactan oligosaccharides to Galectin-3 was also studied by mini-glycochip technique. Galectin-3 displayed strong binding with odd-numbered agaro-pentasaccharide （Galβ1,4anGal（L）-R） and 6-O-sulfated agarose tri- and pentasaccharides （Gal6Sβ1,4anGal（L）-R）, except for recognize regular Galβ1,4GlcNAc structure.The results indicated that sulfated agarose oligosaccharides could be used as Galectin-3 inhibitors, which was applied to the development of new anticancer drugs.更多还原