科學(xué)家發(fā)現(xiàn)了一種冠狀病毒的三維結(jié)構(gòu),。冠狀病毒會造成上呼吸道和胃腸道的炎癥，而且可能導(dǎo)致從SARS到感冒在內(nèi)的疾病,。Abraham Koster及其同事利用一種電子顯微鏡技術(shù)獲得了鼠肝炎冠狀病毒（MHV）及其核糖核蛋白核心的完整圖像。此前，科學(xué)家只有它們的二維圖像,，這妨礙了對該病毒的發(fā)病機制的詳細(xì)研究。
冠狀病毒是一種“包膜”病毒,，這意味著它們的病毒載荷被蛋白質(zhì)覆蓋,，這些蛋白質(zhì)幫助病毒與其宿主融合。這組科學(xué)家證明了鼠冠狀病毒有一個明顯的球形外形,，以及一個厚的異乎尋常的包膜,，幾乎是典型生物膜的厚度的兩倍。他們報告說,，這種額外的厚度是由一種廣泛折疊的蛋白質(zhì)核心而非一個有殼核心構(gòu)成的一個額外的內(nèi)層造成的,。這組作者提出，破解鼠肝炎冠狀病毒的結(jié)構(gòu)可以讓科學(xué)家更好地為該病毒基因組建模,，并提供對哺乳動物病毒結(jié)構(gòu)的更完整的理解,。（生物谷Bioon.com）
生物谷推薦原始出處：
PNAS January 5, 2009, doi: 10.1073/pnas.0805270106
Cryo-electron tomography of mouse hepatitis virus: Insights into the structure of the coronavirion
Montserrat Bárcenaa, Gert T. Oostergetelb, Willem Bartelinkc, Frank G. A. Faasa, Arie Verkleijd, Peter J. M. Rottierc, Abraham J. Kostera,1, and Berend Jan Boschc
aDepartment of Molecular Cell Biology, Electron Microscopy Section, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands
bBiophysical Chemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9497 AG, Groningen, The Netherlands
cDepartment of Infectious Diseases and Immunology, Virology Division, Faculty of Veterinary Medicine, Utrecht University, 3584 CL, Utrecht, The Netherlands; and
dDepartment of Molecular Cell Biology, Utrecht University, 3584 CH, Utrecht, The Netherlands
Edited by Stanley Perlman, University of Iowa, Iowa City, IA, and accepted by the Editorial Board November 20, 2008 (received for review June 3, 2008)
Abstract
Coronaviruses are enveloped viruses containing the largest reported RNA genomes. As a result of their pleomorphic nature, our structural insight into the coronavirion is still rudimentary, and it is based mainly on 2D electron microscopy. Here we report the 3D virion structure of coronaviruses obtained by cryo-electron tomography. Our study focused primarily on the coronavirus prototype murine hepatitis virus (MHV). MHV particles have a distinctly spherical shape and a relatively homogenous size (≈85 nm envelope diameter). The viral envelope exhibits an unusual thickness (7.8 ± 0.7 nm), almost twice that of a typical biological membrane. Focal pairs revealed the existence of an extra internal layer, most likely formed by the C-terminal domains of the major envelope protein M. In the interior of the particles, coiled structures and tubular shapes are observed, consistent with a helical nucleocapsid model. Our reconstructions provide no evidence of a shelled core. Instead, the ribonucleoprotein seems to be extensively folded onto itself, assuming a compact structure that tends to closely follow the envelope at a distance of ≈4 nm. Focal contact points and thread-like densities connecting the envelope and the ribonucleoprotein are revealed in the tomograms. Transmissible gastroenteritis coronavirion tomograms confirm all the general features and global architecture observed for MHV. We propose a general model for the structure of the coronavirion in which our own and published observations are combined.
