研究人員發(fā)現(xiàn)導致這一切的原因就隱藏在病毒的脫氧核糖核酸（DNA）中,。上圖為噬菌體φ29的高分辨率圖像,，它顯示了這種病毒正在被“裝配”的過程——其DNA在病毒的頭與尾之間盤旋。這種緊密的盤旋產生了巨大的壓力,，一旦病毒進入宿主細胞后釋放這種壓力,，便會推進DNA進入后者，這就像一瓶香檳酒的軟木塞在房間中橫沖直撞一樣,。（生物谷www.bioon.com）
生物谷推薦原始出處：
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
[email protected]
Corresponding author
Dwight L. Anderson
[email protected]
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.
