研究人员发现导致这一切的原因就隐藏在病毒的脱氧核糖核酸（DNA）中。上图为噬菌体φ29的高分辨率图像，它显示了这种病毒正在被“装配”的过程——其DNA在病毒的头与尾之间盘旋。这种紧密的盘旋产生了巨大的压力，一旦病毒进入宿主细胞后释放这种压力，便会推进DNA进入后者，这就像一瓶香槟酒的软木塞在房间中横冲直撞一样。（生物谷www.bioon.com）
生物谷推荐原始出处：
Structure，Vol 16, 935-943, 11 June 2008，Jinghua Tang, Timothy S. Baker
DNA Poised for Release in Bacteriophage ø29
Jinghua Tang,1 Norman Olson,1 Paul J. Jardine,2 Shelley Grimes,2 Dwight L. Anderson,2,3, and Timothy S. Baker1,4,
1 Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
2 Department of Diagnostic and Biological Sciences and Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
3 Department of Microbiology, University of Minnesota, Minneapolis, MN 55455, USA
4 Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
Corresponding author
Timothy S. Baker
tsb@ucsd.edu
Corresponding author
Dwight L. Anderson
dlander@umn.edu
Summary
We present here the first asymmetric, three-dimensional reconstruction of a tailed dsDNA virus, the mature bacteriophage 29, at subnanometer resolution. This structure reveals the rich detail of the asymmetric interactions and conformational dynamics of the 29 protein and DNA components, and provides novel insight into the mechanics of virus assembly. For example, the dodecameric head-tail connector protein undergoes significant rearrangement upon assembly into the virion. Specific interactions occur between the tightly packed dsDNA and the proteins of the head and tail. Of particular interest and novelty, an ∼60Å diameter toroid of dsDNA was observed in the connector-lower collar cavity. The extreme deformation that occurs over a small stretch of DNA is likely a consequence of the high pressure of the packaged genome. This toroid structure may help retain the DNA inside the capsid prior to its injection into the bacterial host.
