JOURNAL OF MOLECULAR BIOLOGY | 卷:397 |
Backbone Model of an Aquareovirus Virion by Cryo-Electron Microscopy and Bioinformatics | |
Article | |
Cheng, Lingpeng2  Zhu, Jiang3  Hui, Wong Hoi4  Zhang, Xiaokang2  Honig, Barry3  Fang, Qin1  Zhou, Z. Hong2,4  | |
[1] Chinese Acad Sci, State Key Lab Virol, Wuhan Inst Virol, Wuhan 430071, Peoples R China | |
[2] Univ Calif Los Angeles, Dept Microbiol Mol Genet & Immunol, Los Angeles, CA 90095 USA | |
[3] Columbia Univ, Dept Biochem & Mol Biophys, Howard Hughes Med Inst, Ctr Computat Biol & Bioinformat, New York, NY 10032 USA | |
[4] Univ Calif Los Angeles, Calif NanoSyst Inst, Los Angeles, CA 90095 USA | |
关键词: aquareovirus; dsRNA virus; backbone model; Reoviridae; cryo-electron microscopy; | |
DOI : 10.1016/j.jmb.2009.12.027 | |
来源: Elsevier | |
【 摘 要 】
Grass carp reovirus (GCRV) is a member of the aquareovirus genus in the Reoviridae family and has a capsid with two shells-a transcription-competent core surrounded by a coat. We report a near-atomic-resolution reconstruction of the GCRV virion by cryo-electron microscopy and single-particle reconstruction. A backbone model of the GCRV virion, including seven conformers of the five capsid proteins making up the 1500 molecules in both the core and the coat, was derived using cryo-electron microscopy density-map-constrained homology modeling and refinement. Our structure clearly showed that the amino-terminal segment of core protein VP3B forms an similar to 120-angstrom-long alpha-helix-rich extension bridging across the icosahedral 2-fold-symmetry-related molecular interface. The presence of this unique structure across this interface and the lack of an external cementing molecule at this location in GCRV suggest a stabilizing role of this extended amino-terminal density. Moreover, part of this an-Lino-terminal extension becomes invisible in the reconstruction of transcription-competent core particles, suggesting its involvement in endogenous viral RNA transcription. Our structure of the VP1 turret represents its open state, and comparison with its related structures at the closed state suggests hingelike domain movements associated with the mRNA-capping machinery. Overall, this first backbone model of an aquareovirus virion provides a wealth of structural information for understanding the structural basis of GCRV assembly and transcription. (c) 2009 Published by Elsevier Ltd.
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