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Naitow H, Hamaguchi T, Maki-Yonekura S, Isogai M, Yoshikawa N, Yonekura K. Apple latent spherical virus structure with stable capsid frame supports quasi-stable protrusions expediting genome release. Commun Biol 2020; 3:488. [PMID: 32887929 PMCID: PMC7474077 DOI: 10.1038/s42003-020-01217-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Accepted: 08/11/2020] [Indexed: 01/30/2023] Open
Abstract
Picorna-like plant viruses are non-enveloped RNA spherical viruses of ~30 nm. Part of the survival of these viruses depends on their capsid being stable enough to harbour the viral genome and yet malleable enough to allow its release. However, molecular mechanisms remain obscure. Here, we report a structure of a picorna-like plant virus, apple latent spherical virus, at 2.87 Å resolution by single-particle cryo-electron microscopy (cryo-EM) with a cold-field emission beam. The cryo-EM map reveals a unique structure composed of three capsid proteins Vp25, Vp20, and Vp24. Strikingly Vp25 has a long N-terminal extension, which substantially stabilises the capsid frame of Vp25 and Vp20 subunits. Cryo-EM images also resolve RNA genome leaking from a pentameric protrusion of Vp24 subunits. The structures and observations suggest that genome release occurs through occasional opening of the Vp24 subunits, possibly suppressed to a low frequency by the rigid frame of the other subunits.
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Affiliation(s)
- Hisashi Naitow
- Biostructural Mechanism Laboratory, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo, 679-5148, Japan
| | - Tasuku Hamaguchi
- Biostructural Mechanism Laboratory, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo, 679-5148, Japan
| | - Saori Maki-Yonekura
- Biostructural Mechanism Laboratory, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo, 679-5148, Japan
| | - Masamichi Isogai
- Plant Pathology Laboratory, Faculty of Agriculture, Iwate University, Ueda 3-chome 18-8, Morioka, Iwate, 020-8550, Japan
| | - Nobuyuki Yoshikawa
- Agri-Innovation Center, Iwate University, Ueda 3-chome 18-8, Morioka, Iwate, 020-8550, Japan
| | - Koji Yonekura
- Biostructural Mechanism Laboratory, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo, 679-5148, Japan. .,Advanced Electron Microscope Development Unit, RIKEN-JEOL Collaboration Center, RIKEN Baton Zone Program, 1-1-1 Kouto, Sayo, Hyogo, 679-5148, Japan.
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