3j17

Structure of a transcribing cypovirus by cryo-electron microscopy

Loading... Status: waiting for Mol* initialization Structural highlights 3j17 is a 5 chain structure with sequence from Bombyx mori cypovirus 1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 4.1Å Ligands: GPL Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q914N6_CPVBM Publication Abstract from PubMed Double-stranded RNA viruses in the family Reoviridae are capable of transcribing and capping nascent mRNA within an icosahedral viral capsid that remains intact throughout repeated transcription cycles. However, how the highly coordinated mRNA transcription and capping process is facilitated by viral capsid proteins is still unknown. Cypovirus provides a good model system for studying the mRNA transcription and capping mechanism of viruses in the family Reoviridae. Here, we report a full backbone model of a transcribing cypovirus built from a near-atomic-resolution density map by cryoelectron microscopy. Compared with the structure of a nontranscribing cypovirus, the major capsid proteins of transcribing cypovirus undergo a series of conformational changes, giving rise to structural changes in the capsid shell: (i) an enlarged capsid chamber, which provides genomic RNA with more flexibility to move within the densely packed capsid, and (ii) a widened peripentonal channel in the capsid shell, which we confirmed to be a pathway for nascent mRNA. A rod-like structure attributable to a partially resolved nascent mRNA was observed in this channel. In addition, conformational change in the turret protein results in a relatively open turret at each fivefold axis. A GMP moiety, which is transferred to 5'-diphosphorylated mRNA during the mRNA capping reaction, was identified in the pocket-like guanylyltransferase domain of the turret protein. Cryo-EM structure of a transcribing cypovirus.,Yang C, Ji G, Liu H, Zhang K, Liu G, Sun F, Zhu P, Cheng L Proc Natl Acad Sci U S A. 2012 Apr 17;109(16):6118-23. doi:, 10.1073/pnas.1200206109. Epub 2012 Apr 6. PMID:22492979 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Virus coat proteins 3D structures

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