發展具潛力的法呢基轉移酶抑制劑:虛擬嵌合與篩選研究

Developing Potential Inhibitors of Farnesyltransferase by Virtual Screening and Docking Studies

蘇芳玉(Fang-Yu Su)

指導教授 ： 林榮信

共同指導教授 ： 陳基旺(Ji-Wang Chern)

國立臺灣大學/醫學院/藥學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.01220

摘要

近年來由於X射線晶格繞射以及核磁共振等技術的發展，生物分子的三維結構被大規模快速測定，釵h作為藥物標的的蛋白質從而可以進行基於結構的藥物設計與篩選，而在抗癌藥物開發上亦已有釵h應用，法呢基轉移酶 (Farnesyltransferase，FT) 則是其中一個新穎的抗癌藥物的標的。法呢基作用為Ras蛋白質轉錄後修飾作用的第一步，致癌蛋白質Ras需要經過法呢基轉移酶修飾，始能展現其生物活性。因此，若法呢基作用這個過程被抑制的話，就能抑制Ras活性，使得細胞增生相關的機制受阻，最後抑制癌細胞生長。法呢基轉移酶進行法呢基作用的時候，會將farnesyl group 接到蛋白質上，使之脂溶性增加，進而得以嵌接到細胞膜上。有鑑於此，釵h國外的大藥廠皆積極地尋找法呢基轉移酶的抑制劑以作為新的抗癌藥物。
在本論文中，本實驗室利用電腦輔助藥物設計的方式，運用層秩式 (hierarchical)的篩選，以尋找法呢基轉移酶抑制劑的先導化合物。篩選層級包括子結構的搜尋、分子量的限制和嵌合模擬。嵌合 (docking) 是將小分子配體放置於受體的活性位置處，並尋找出嵌合最好的的取向 (orientation) 和構形。我們運用嵌合法從小分子資料庫中搜尋與受體生物大分子有較好結合性的配體，從中發現新的先導化合物。我們利用了嵌合程式DOCK4.01和AutoDock3.05，對ACD (Available Chemical Directory) 資料庫進行虛擬篩選 (virtual screening)，試圖從此資料庫找出可能有效的化合物。利用本論文提出之層秩式篩選方法應用於藥物研究，可以大大加快發現先導化合物的速度。我們利用ISIS/BASE找出分子量低於700的化合物，並利用嵌合模擬找出化合物與蛋白質之間的辨識方式。在此次研究工作中，我們最後找到15個作用在同樣活化位置上的新穎化合物。這些新穎先導化合物之後在結合生物及生化活性試驗，利用先導化合物優化 (lead optimization) 以開發新的抗癌藥物。

關鍵字

法泥基轉移酶虛擬塞選

並列摘要

In the last decades, X-Ray Diffraction (XRD) and Nuclear Magnetic Resonance (NMR) are well developed, that make many pharmaceutical 3D structures of relevant targets available. Farnesyltansferase (FT) is one of most well-studied anti-cancer therapeutic target. FT is a critical enzyme that post-translationally modifies Ras oncoproteins. Inhibitors of farnesyl- transferase (FTIs) cause suppression of transforming activity of Ras oncoproteins, and therefore FTIs could be used as anti-cancer agents.
In our study, a hierarchical virtual screening scheme which has been employed combines pharmacophore filtering, molecular weight filtering, and docking. ACD (Available Chemical Directory) is utilized as the basic chemical database and in the first filtering step using substructure constructed from known potent FTIs performed are chosen as candidates. Then only the chemical compounds with molecular weights less than 700 Da are selected to perform the second stage filtering. Finally DOCK4.01 and AutoDock3.05 are used to simulate the molecular recognition process for FT and its inhibitors. We have found several compounds with high score, and some of them exhibit key interactions with zinc at important residues in the active site.
The discovered FTIs novel lead interact with the relative residues in the active site, they may be strong candidates for anti-tumor therapy. Energy calculation of compounds may support the interactions between structures and activities of these FTs. It will also help the lead optimization and novel drug design in the future.

並列關鍵字

farnesyltransferase docking

參考文獻

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