Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/36088
標題: 竹嵌紋病毒三重疊基因區第一轉譯蛋白之功能特性分析
Analyses of the functional properties of the triple gene block protein 1 of bamboo mosaic potexvirus
作者: 劉淡英
Liou, Dann-Ying
關鍵字: bamboo mosaic virus
竹嵌紋病毒
triple gene block
inclusion body
RNA-binding activity
NTP-binding activity
NTPase
renaturation
NTP-binding
三重疊基因區
蛋白聚結體
RNA 結合活性
NTP 結合活性
NTP 水解活性
重新摺疊
NTP 結合區域
出版社: 農業生物科技學研究所
摘要: 竹嵌紋病毒 (bamboo mosaic virus,簡稱BaMV) 三重疊基因區 (triple gene block) 之轉譯蛋白與該病毒於細胞間的轉移有關,其中第一轉譯蛋白 (28 kDa) 於感染竹嵌紋病毒之植物葉細胞中會形成不溶性的蛋白聚結體,且其外圍發現有病毒顆粒的存在,此現象似乎意味著這些28 kDa蛋白聚結體,可能為該轉移蛋白的活性區域之一。利用有機溶劑萃取、差異性離心法、以及蔗糖密度梯度離心法,可由感染竹嵌紋病毒的白蔾葉肉細胞中純化出28 kDa蛋白之不溶性聚結體。此不溶性聚結體具有NTP-binding及NTPase二種活性,但不具RNA-binding活性;相較下,大腸桿菌所生產且經由相同純化方法所獲得的28 kDa蛋白不溶性聚結體,則無上述活性,可見植物來源與細菌來源的28 kDa蛋白聚結體並不具有相同的功能構造。上述二種來源之28 kDa蛋白經變性處理、重新摺疊後所形成的可溶性部分蛋白,除了具有NTP-binding及NTPase活性外,亦具有RNA-binding的能力。推測竹嵌紋病毒的28 kDa蛋白於植物細胞中可能具有二種功能形態,一為水溶性狀態,另一則以不溶性之聚結體存在,此二種形態之蛋白於病毒轉移過程中,可能扮演著不同的角色。另外,原本對28 kDa蛋白之RNA-binding能力有重要性影響之Arg16及Arg21,於本實驗中亦證得為該蛋白NTP-binding及NTPase活性發揮之所需。由於這二個必要之arginine所在區域位於一般NTP-binding motif的保守性區域 (conserved region) 之外,說明此28 kDa蛋白可能存在一個未被定義的NTP-binding region.
The 28 kDa protein of Bamboo mosaic potexvirus (BaMV) is encoded by the first overlapping gene of the triple-gene-block whose products are thought to play roles in virus movement between cells. This protein was found to form inclusion bodies associated with virus particles in the BaMV-infected tissues. Thus, it is highly possible that the 28 kDa protein inclusions is an active source of the protein. To prove this idea, we purified the 28 kDa protein inclusions from the BaMV-infected tissues of Chenopodium quinoa by organic solvent clarification, differential centrifugation and sucrose density gradient centrifugation. The 28 kDa protein inclusions possessed the NTP-binding and NTPase activity, but were unable to bind RNA. In contrast, the 28 kDa inclusions from Escherichia coli did not have any of such activities, indicating that the 28 kDa protein inclusions of different origins are not in the same conformation. Since the soluble fraction of the 28 kDa proteins of these two origins shared the same RNA-binding, NTP binding and NTPase activities after denaturation and renaturation, we propose that the 28 kDa protein of BaMV assumes two different functional forms. One is soluble; the other is in the form of protein inclusion. The two forms of the 28 kDa protein may play different roles in the process of virus movement. We also mapped Arg16 and Arg21, which are critical to RNA binding, are also required for NTP-binding or NTPase activities of the 28 kDa protein. The localization of these two essential arginines outside the conserved regions of the known NTP-binding motif indicates that a new NTP-binding region is present in the 28 kDa protein.
URI: http://hdl.handle.net/11455/36088
Appears in Collections:生物科技學研究所

文件中的檔案:

取得全文請前往華藝線上圖書館



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.