利用分子接合建立高速虛擬平台用於篩選登革熱蛋白□抑制劑

Abstract

登革熱病毒(dengue virus)屬於Flaviviridae之中的flavivirus ，依其抗原性，共可分為四個血清型。病毒粒子具有套膜，為正股RNA病毒，其上有一個 ORF。在表現時，會先產生一條polypeptide，接著再經由病毒或寄主的protease切割與修飾，產生10個有活性的蛋白質產物，其中，在非結構蛋白中的NS3蛋白質，同時具有Serine protease及helicase的酵素活性，因此，在切割非結構蛋白與病毒複製的過程中，扮演著重要的角色。若能阻斷其功能，應可對病毒之複製有抑制作用，這也是本論文主要想探討與研究的部份。

前登革熱，並無有效之疫苗，且缺乏專一性治療藥物，因此對患者多採支持性療法。所以，希望能找到一個小分子化合物，能夠與NS3 protease的活性結合部位，進行專一性的結合，阻斷原有的生化途徑抑制其酵素活性，而達到抑制病毒複製的效果，進而篩選出可能運用於治療登革熱病毒上的相關藥物。

我們運用分子接合 (Molecular docking) 的方法，依Look and Key 的形狀互補與電荷互補的理論，從已知的蛋白質結晶結構，鑑定與分析受質的活性結合區域，接著去MDDR藥物資料庫做docking，利用電腦模擬，來尋找出潛在可能抑制NS3 protease的小分子化合物及其兩者之間的最佳的結合模式。依據上述的分析過程，希望能在龐大的資料庫中，找出能與NS3 protease 之間有最佳結合方式的化合物並建立小量資料庫篩選系統與分析方法。最後可再進一步經由實驗，印證我們的結果。這樣的方法，可以提高藥物研究與開發的速率並降低研究成本。

Dengue virus is a members of the family Flaviviridae. There are four serotypes for dengue virus. Up to now,there still has no effective vaccine and specified medicine for dengue virus.There is only supportive treatment for patients. The dengue virus is enveloped and contains a single, positive-sense RNA genome about 11 KB which encodes a large polyprotein precursor. Flavivirus is dependent on correct cleavage of this polypeptide and it will produce 10 active protein products. NS3 protein, one of the non-structure proteins, has enzyme activity of both serine protease and helicase. Thus, it plays an important role in the polypeptide processing and virus replication. If one blocks its function, one may inhibit virus replication, which is the main issue of this study. To reach the goal, I hope that I can find small molecules which can bind the active site of NS3 protease and then inhibit its biological function to reach the purpose of inhibiting the replication of dengue virus. As the first step to screen the leads which can inhibit dengue virus NS3 protease, I use the tool of molecular docking. It is based on the match of small molucules and target proteins. In other words, I use the measure of complement mutual compensation of molecular shape between Lock and Key theory and force-field interaction. Using the computer simulation, I can find the best combining model of chemicals. Counting on the previous process of analysis and enormous database, I aimed to find the potential small molecular hits which can inhibit NS3 protease. In this way, I has show that this method can facilitate the medicine research and innovation to reduce the costs of research.