title: Cryo-EM structures of two bovine adenovirus type 3 intermediates.
abstract: Adenoviruses (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.
authors: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors: Lingpeng
authors: L
authors: Cheng
authors: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors: Xiaoxing
authors: X
authors: Huang
authors: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors: Xiaomin
authors: X
authors: Li
authors: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Luo-jia-shan, Wuhan, Hubei 430072, China.
authors: Wei
authors: W
authors: Xiong
authors: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors: Wei
authors: W
authors: Sun
authors: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors: Chongwen
authors: C
authors: Yang
authors: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors: Kai
authors: K
authors: Zhang
authors: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors: Ying
authors: Y
authors: Wang
authors: College of Physics and Information Science, Hunan Normal University, Changsha, Hunan 410081, China.
authors: Hongrong
authors: H
authors: Liu
authors: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors: Xiaojun
authors: X
authors: Huang
authors: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors: Gang
authors: G
authors: Ji
authors: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors: Fei
authors: F
authors: Sun
authors: State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Luo-jia-shan, Wuhan, Hubei 430072, China. Electronic address: cctcc202@whu.edu.cn.
authors: Congyi
authors: C
authors: Zheng
authors: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: zhup@ibp.ac.cn.
authors: Ping
authors: P
authors: Zhu
mesh_terms: D000257:Adenoviridae Infections / Q000662:veterinary* / Q000821:virology*; D000260:Adenoviruses, Human / Q000235:genetics / Q000502:physiology / Q000648:ultrastructure; D000818:Animals; D002213:Capsid / Q000378:metabolism / Q000648:ultrastructure; D002417:Cattle; D002418:Cattle Diseases / Q000821:virology*; D002460:Cell Line; D020285:Cryoelectron Microscopy; D006801:Humans; D017921:Mastadenovirus / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure*; D019065:Virus Assembly
keywords: Adenovirus assembly; Bovine adenovirus; Polypeptide VI; Subviral particles