T4病毒的DNA需要在特定分子馬達(dá)的幫助下,，才能進(jìn)入病毒的蛋白殼內(nèi)。Purdue大學(xué)和美國Catholic大學(xué)的研究人員最近發(fā)現(xiàn)了一種在此機(jī)制中扮演重要角色的酶：三磷酸腺苷酶（ATPase）的結(jié)構(gòu),。這篇文章第一作者為Purdue大學(xué)科學(xué)院Michael Rossmann實驗室博士后研究員Siyang Sun,。研究內(nèi)容刊載3月22日的Molecular Cell中。
這種分子馬達(dá)在其它病毒中也存在,，包括人類皰疹病毒,。病毒首先組裝蛋白頭部的蛋白殼，然后將DNA裝入空的衣殼中,。這種過程可以比喻為建造房屋，然后添加家具,。
DNA記錄了病毒的全部特征,，衣殼保護(hù)了這種記錄，確保病毒能夠通過感染宿主不斷繁殖,。ATPase將ATP降解為ADP時,，產(chǎn)生包裝所需的能量。ATPase可破壞磷酸鹽和ADP之間的化學(xué)鍵,。
研究人員將運(yùn)轉(zhuǎn)T4病毒的分子馬達(dá)所需的ATPase結(jié)構(gòu),，與解旋酶（helicases）的結(jié)構(gòu)進(jìn)行比對,，推測出一種可能的馬達(dá)運(yùn)作機(jī)制。
解旋酶是在基因復(fù)制過程中將雙鏈DNA分開為單鏈的酶,。DNA復(fù)制過程中,，解旋酶會選擇性結(jié)合或脫離DNA，沿著螺旋移動將雙鏈分為單鏈,。研究人員推測病毒的分子馬達(dá),，也是利用相似的機(jī)制將DNA擠入病毒中。
研究人員利用X射線結(jié)晶學(xué)技術(shù)分析了ATPase的結(jié)構(gòu),。這項研究結(jié)果有助于設(shè)計出可干擾這些病毒分子馬達(dá)的藥物,，以治療病毒感染、發(fā)展微型的納米馬達(dá),。
(資料來源 : Bio.com)
部分英文原文：
Molecular Cell, Vol 25, 943-949, 23 March 2007
Short Article
The Structure of the ATPase that Powers DNA Packaging into Bacteriophage T4 Procapsids
Siyang Sun,1 Kiran Kondabagil,2 Petra M. Gentz,1,3 Michael G. Rossmann,1, and Venigalla B. Rao2,
1 Department of Biological Sciences, Purdue University, 915 W. State Street, West Lafayette, IN 47907, USA
2 Department of Biology, The Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064, USA
Corresponding author
Michael G. Rossmann
[email protected]
Corresponding author
Venigalla B. Rao
[email protected]
Summary
Packaging the viral genome into empty procapsids, an essential event in the life cycle of tailed bacteriophages and some eukaryotic viruses, is a process that shares features with chromosome assembly. Most viral procapsids possess a special vertex containing a dodecameric portal protein that is used for entry and exit of the viral genome. The portal and an ATPase are parts of the genome-packaging machine. The ATPase is required to provide energy for translocation and compaction of the negative charges on the genomic DNA. Here we report the atomic structure of the ATPase component in a phage DNA-packaging machine. The bacteriophage T4 ATPase has the greatest similarity to monomeric helicases, suggesting that the genome is translocated by an inchworm mechanism. The similarity of the packaging machines in the double-stranded DNA (dsDNA) bacteriophage T4 and dsRNA bacteriophage 12 is consistent with the evolution of many virions from a common ancestor.
英文全文鏈接：http://www.molecule.org/content/article/fulltext?uid=PIIS109727650700113X
