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Picornavirus uncoating intermediate captured in atomic detail.
Jingshan Ren1, Xiangxi Wang, Zhongyu Hu
1Division of Structural Biology, University of Oxford, Headington, Oxford, UK.
Nature Communications
|June 4, 2013
Summary
This study reveals the atomic structure of a picornavirus uncoating intermediate, showing how viral proteins exit the capsid to infect host cells. This finding clarifies a key step in viral genome delivery and host cell entry.
Area of Science:
- Virology
- Structural Biology
- Molecular Biology
Background:
- Viral genome delivery into host cells is a critical, yet poorly understood, step in viral infection.
- Non-enveloped viruses, like picornaviruses, require specific mechanisms to transfer their genetic material across cellular membranes.
- Picornaviruses, including human pathogen CAV16, initiate uncoating via particle expansion, exposing potential exit routes.
Purpose of the Study:
- To elucidate the atomic structure of an uncoating intermediate of the human picornavirus CAV16.
- To visualize the mechanism of viral capsid protein extrusion and genome release.
- To propose a detailed hypothesis for the ordered egress of internal viral components.
Main Methods:
- Atomic resolution structural analysis of a picornavirus uncoating intermediate.
- Integration of low-resolution data with high-resolution structural information.
- Comparative analysis with known picornavirus uncoating mechanisms.
Main Results:
- The atomic structure reveals a picornavirus protein (VP1) partially extruded from the capsid.
- This intermediate structure suggests VP1 is poised for membrane insertion, facilitating host cell entry.
- Two distinct channel systems within the capsid are implicated in the ordered release of internal proteins.
Conclusions:
- The study provides the first atomic view of a picornavirus uncoating intermediate, detailing protein extrusion.
- A mechanism for ordered protein and genome egress through capsid channels is proposed.
- A potential structural link between condensed viral RNA and the triggering of RNA release is suggested.
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