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Cryo-EM structures of two intermediates provide insight into adenovirus assembly and disassembly
Structural highlights
FunctionCAPSH_ADEB3 Major capsid protein that self-associates to form 240 hexon trimers, each in the shape of a hexagon, building most of the pseudo T=25 capsid. Assembled into trimeric units with the help of the chaperone shutoff protein. Transported by pre-protein VI to the nucleus where it associates with other structural proteins to form an empty capsid. Might be involved, through its interaction with host dyneins, in the intracellular microtubule-dependent transport of incoming viral capsid to the nucleus (By similarity). Publication Abstract from PubMedAdenoviruses (Ads) infect hosts from all vertebrate species and have been investigated as vaccine vectors. We report here near-atomic structures of two bovine Ad type 3 (BAd3) intermediates obtained by cryo-electron microscopy. A comparison between the two intermediate structures reveals that the differences are localized in the fivefold vertex region, while their facet structures are identical. The overall facet structure of BAd3 exhibits a similar structure to human Ads; however, BAd3 protein IX has a unique conformation. Mass spectrometry and cryo-electron tomography analyses indicate that one intermediate structure represents the stage during DNA encapsidation, whilst the other intermediate structure represents a later stage. These results also suggest that cleavage of precursor protein VI occurs during, rather than after, the DNA encapsidation process. Overall, our results provide insights into the mechanism of Ad assembly, and allow the first structural comparison between human and nonhuman Ads at backbone level. Cryo-EM structures of two bovine adenovirus type 3 intermediates.,Cheng L, Huang X, Li X, Xiong W, Sun W, Yang C, Zhang K, Wang Y, Liu H, Huang X, Ji G, Sun F, Zheng C, Zhu P Virology. 2014 Feb;450-451:174-81. doi: 10.1016/j.virol.2013.12.012. Epub 2014, Jan 3. PMID:24503080[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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