抑制疱疹一型病毒進入宿主細胞之特定3-氧-磺酸化肝素八醣體的全合成研究

Total Synthesis of a Specific 3-O-Sulfonated Heparin Octasaccharide that Inhibits Entry of Herpes Simplex Virus Type 1 to the Host Cell

林書顗(Shu-Yi Lin)

指導教授 ： 洪上程 ； 林俊成

國立清華大學/理學院/化學系/博士(2010年)

摘要

第一型單純疱疹病毒(HSV-1)屬於親神經元性病毒，為常見的病原體，一旦感染後便會不斷的復發，難以根冶。根據文獻研究，在病毒入侵宿主細胞時，細胞表面的硫酸乙醯肝素(HS)扮演了很重要的角色，不僅可幫助病毒附著於細胞表面，也是病毒上醣蛋白與細胞結合的關鍵受器，經由這些步驟病毒才能感染宿主細胞，並進而複製繁衍。2008年，劉建教授利用以3-O-磺基化酵素修飾過後，具有3-O-磺酸基的肝素八醣體2，經由測試發現可以有效的抑制HSV-1的感染入侵。但利用酵素方法無從得知其確切結構，且無法大量製備，因此，本論文主要工作便是以化學合成的方式，製備出具有特定3-O-磺酸基的肝素八醣體。 這篇論文分成九個章節，第一章主要是在簡介疱疹病毒與宿主細胞表面的硫酸乙醯肝素的作用關係，並將重點著重於具特定3-O-磺酸基的硫酸乙醯肝素。第二章為針對近幾年來，有關合成肝素八醣或八醣以上的文章，做概略的介紹。第三章則提出想要合成的目標分子，並試著將目標分子進行逆合成分析。 第四章為探討D式葡萄胺醣的醣苷鍵位向控制，從改變醣予體的保護基上著手，探討了各種不同的組合，並考慮立體障礙的因素，最終得到了一種最佳的保護基組合，除了醣上每一個保護基皆具有交錯且不互相干擾的特性以外，在進行醣鏈結反應時可得到單一位向的雙醣產物100。第五章則是利用一共同雙醣中間體100，經由幾步官能基轉換和選擇性去保護的方式，可以獲得不同的雙醣衍生物63, 121, 122。 第六章描述如何建構八醣骨架，一開始由非還原端來建構六醣體的骨架，在遇到了一些問題以後，我們將合成策略改由還原端來建立六醣體的骨架，接著將六醣體133轉換為醣予體，進行兩次醣鏈結反應後，獲得全保護的八醣體150。接著在第七章經由七步去保護和官能基轉換，可順利得到最終產物57，經活性測試後，確實具有抑制第一型疱疹感染的效果，未來可進一步探討八醣體57與HSV-1的gD之間的作用關係，並提供更多的資訊，以幫助抗HSV-1的新藥開發。 第八章結論則是將第四章至第七章的工作做統整報告；而本論文工作中化合物的物理性質和詳細實驗步驟則列於第九章。

關鍵字

單純性疱疹病毒第一型 ； 3-氧-磺酸化肝素 ； 肝素 ； 硫酸乙醯肝素

並列摘要

Herpes simplex virus type 1 (HSV-1), a prevalent human pathogen causing chronic and recurrent lesions, belongs to the neurotropic subgroup of the herpes virus family. Cell surface heparan sulfate (HS) plays dual roles not only for assisting attachment of HSV-1 to the host cell, but also for inducing entry of the virus into the target cell. In 2008, Jian Liu identified that the specific 3-O-sulfonated octasaccharide 2, generated by enzymatic sulfonation of a heparin-degraded octasaccharide at the 3-O position of the second D-glucosamine unit from the reducing end, inhibited attachment and entry processes to the host cell during HSV-1 infection. However, the enzymatic synthesis may not be applicable in preparing the material in large scale. In addition, the exact HS structure was also not clearly defined. This dissertation is concerned with the development of methodologies for the synthesis of 3-O-sulfonated HS octasaccharide.
Chapter 1 begins with a description of the relationship about herpes virus and heparan sulfate on host cell surface, especially the role of 3-O-sulfonated HS in virus infection. Chapters 2 provides a brief introduction, and reviews the literature on the synthesis of heparin octasaccharide or longer sugar chain in recent years. The specific aims and the retro-synthetic plans of the new preparative approach are illustrated in Chapter 3.
Chapter 4 describes the stereoselective glycosylation of D-glucosamine. The roles of different protecting groups on the D-glucosamine donors are investigated, leading to the successful development of a powerful glycosyl donor for the formation of disaccharide 100 in high stereoselectivity and good yields. The conversion of the dual purpose disaccharide 100 into 63, 121, and 122 through functional group transformation or via regioselective deprotection is discussed in chapter 5.
Chapter 6 elaborates the construction of HP/HS oligosaccharide skeleton. The synthesis of the hexasaccharide 133 was carried out through a [2+2+2] reducing end to nonreducing end fashion and transformed into a glycosyl donor. Coupling of hexasaccharide donor with the 4-alcohol 60 followed by removal of the 2-naphthylmethyl (2-NAP) group and glycosidation with the L-idopyranosyl donor 59 generated the fully protected octasaccharide. After a series of functional group deprotection and transformations from fully protected octasaccharide, the final product 57 was acquired and subjected to bioassays, as specified in Chapter 7. In the future, interaction between 57 and HSV-1 glycoprotein gD, particularly, the complex structure at the molecular level, will be further studied to provide valuable information for the discovery of new anti-HSV-1 drugs.
The conclusion of this work is summarized in Chapter 8. Finally, Chapter 9 provides the detailed experimental section and the characterization of new compounds.

並列關鍵字

HSV-1 ； 3-O-Sulfonated Heparin ； Heparin ； Heparan sulfate

參考文獻

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