The cryo-EM structure of infectious bursal disease virus with different virulence strains helps to understand its assembly and invasion mechanism

Infectious bursal disease virus (IBDV) is an important representative of the biRNAvirus family
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The infectious bursal disease (IBD) caused by it is an important immunosuppressive disease that endangers the healthy development of the poultry industry and causes serious economic losses
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The crystal structure of IBDV T=1 subviral particle (SVP) has been reported, but the whole virus structure of IBDV super virulent strain (vvIBDV) and attenuated strain has not yet been resolved, which is important for understanding the molecular mechanism of IBDV assembly and invasion.
Very important
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Zhu Ping's team from Institute of Biophysics, Chinese Academy of Sciences and Wang Xiaomei's team from Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences/World Organization for Animal Health (OIE) IBD Reference Laboratory recently published an article "Cryo-EM structures of infectious bursal disease" in Science Bulletin viruses with different virulences provide insights into their assembly and invasion"
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The study used cryo-electron microscope three-dimensional reconstruction technology to analyze the high resolution of 3.
3 Å and 3.
2 Å of the vvIBDV Gx strain with high lethality and not suitable for in vitro cell culture, and the attenuated strain Gt whole virus that is not pathogenic but suitable for in vitro cell culture.
Rate structure
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Compared with the structure of T=1 SVP, the IBDV T=13 whole virus structure analyzed in this study shows some unique and conservative structural features, especially the N-terminus of the flexible structural protein VP2 in SVP, at T=13 The whole virus interacts with the β bundle SF of the adjacent VP2 trimer S domain to form a β sheet.
This interaction “tethers” the adjacent VP2 trimers together and helps the virus to assemble and stabilize
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The comparison of the structure of the two different virulent strains showed that compared with the vvIBDV Gx strain, the attenuated strain Gt formed a hydrogen bond between H254 and T284 in the VP2P domain and showed a positive surface potential, which suggested the 253/284 mutation of VP2 And the corresponding changes in surface potential may be an important mechanism for the differences in cell tropism of different strains
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In addition, the surface of VP2 contains a groove with a negative surface potential.
The groove contains the integrin binding motif IDA, which plays an important role in the process of virus invasion of cells, and may play an important role in the process of IBDV invasion
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This research is of great significance for in-depth analysis of the infection and pathogenic mechanism of IBDV
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Dr.
Bao Keyan from the Institute of Biophysics, Chinese Academy of Sciences and researcher Qi Xiaole from the Harbin Veterinary Research Institute of the Chinese Academy of Agricultural Sciences are the co-first authors of the study.
Researcher Zhu Ping from the Institute of Biophysics of the Chinese Academy of Sciences and researcher Wang Xiaomei from the Harbin Veterinary Research Institute of the Chinese Academy of Agricultural Sciences are the co-corresponding authors Dr.
Li Yan and Dr.
Gong Minqing from the Institute of Biophysics, Chinese Academy of Sciences also contributed to this research
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The research was supported by the National Natural Science Foundation of China (U20A2061, 3173023, 31521002, 32072852), the Strategic Key Research and Development Program of the Chinese Academy of Sciences (XDB37010100), the Key Project of the State Key Laboratory of Veterinary Biotechnology (SKLVBF201702), and the Project of the State Key Laboratory of Biomacromolecules ( 2020KF12) and other funding
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