一鍋化醣鏈結來合成胚胎幹細胞表面醣體與跟流感病毒結合之寡醣

One-pot Glycosylation for the Synthesis of Embryonic Stem Cell Surface Carbohydrates and Influenza Virus-binding Oligosaccharides

徐昀(Hsu, Yun)

指導教授 ： 洪上程 ； 廖文峯

國立清華大學/理學院/化學系/博士(2013年)

摘要

Abstract
This thesis describes the development of one-pot methodologies for the syntheses of influenza virus-binding oligosaccharides and embryonic stem cell-surface carbohydrates, including their bioanalysis. The synthesis also included regioselective protection of the individual hydroxyl groups of monosaccharides to form sugar building blocks.
One-pot protocols were utilized to assemble sialic acid-containing trisaccharides, which were deprotected to form sugar libraries carrying Neu5Ac or Neu5Gc residues. The bioassay results for these compounds correspond with the suggestion that Neu5Gc have marked influence in the interaction with other biological agents. Neu5Gc-containing compounds have the potential as anti-flu drugs because of their stronger ability to associate with viral particles. The developed one-pot glycosylation protocol is notable for building the oligosaccharides starting from the non-reducing end sialic acid residue towards the reducing end and the formation of three glycosidic bonds leading also to the synthesis of pentasaccharides and tetrasaccharides. Data from Surface plasmon resonance (SPR) showed that the pentasaccharide has ten times greater binding affinity than the tetrasaccharide. Regarding the embryonic stem cell surface carbohydrates, the one-pot assembly and eventual synthesis of Lc4 and IV2Fuc-Lc4 were carried out. The binding affinity of these oligosaccharides with galectin-1 protein were measured using ITC and the synthetic sugars were further attached to a protein for vaccine evaluation in animals.

關鍵字

一鍋化醣鏈結 ； 唾液酸

並列摘要

摘要

本論文的主要研究是發展一鍋化醣鏈結方式合成與流感病毒結的結合的寡醣分子跟胚胎幹細胞表面的醣體與其生化測試。同時結合了單醣一鍋化保護策略，在單一反應中依序進行多步的化學反應，進而區分並保護醣體上的各個羥基，並得到所需的單醣建構單元。
一鍋化合成三醣分子庫，經去保護分別合成含有Neu5AC 與 Neu5GC的唾液酸三醣分子，並且針對人類流感病毒來做抑制能力的測試，實驗結果跟本實驗室所假設理論符合。Neu5Gc 與病毒結合能力比 Neu5Ac來的好，這或許具有發展克流感藥物的潛力。而一鍋化合成唾液酸寡醣的實驗，突破了以往的限制，成功從唾液酸非還原端開始建立起三個醣苷鍵，合成出四醣與五醣分子庫。從表面電漿子共振 (SPR) 實驗結果顯示，唾液酸五醣體與血球凝結素結合能力與四醣好上十倍。也利用一鍋化來合成胚胎幹細胞表面的醣體，針對 Lc4與 IV2Fuc-Lc4 於合成上與生化上探討。量測 Lc4與 IV2Fuc-Lc4 對於半乳糖凝集素 (Galectin-1) 的結合能力，也嘗試著製備其醣蛋白疫苗對活體動物來實驗。

參考文獻

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