Identification of the Active Sites in the Methyltransferases of a Transcribing dsRNA Virus
| Autor: | Lingpeng Cheng, Feng Song, Chongwen Yang, Xiaojun Huang, Bin Zhu, Ping Zhu, Songjun Zeng, Hongrong Liu, Gang Ji |
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| Rok vydání: | 2014 |
| Předmět: |
Models
Molecular SAH S-adenosyl-l-homocysteine GTase guanylyltransferase Methyltransferase RNA capping Transcription Genetic RNA methylation viruses RNA-dependent RNA polymerase Reoviridae Protein Structure Secondary Article ICP inner capsid particle Structural Biology Icosahedral viral capsid Catalytic Domain RNA methyltransferase Viral Regulatory and Accessory Proteins dsRNA virus Protein Structure Quaternary cryo-EM cryo-electron microscopy Molecular Biology RNA Double-Stranded MTase methyltransferase Genetics biology RNA Methyltransferases biology.organism_classification SAM S-adenosyl-l-methionine Cell biology RNA silencing RNA Viral dsRNA double-stranded RNA Cypovirus |
| Zdroj: | Journal of Molecular Biology |
| ISSN: | 0022-2836 |
| DOI: | 10.1016/j.jmb.2014.03.013 |
| Popis: | Many double-stranded RNA (dsRNA) viruses are capable of transcribing and capping RNA within a stable icosahedral viral capsid. The turret of turreted dsRNA viruses belonging to the family Reoviridae is formed by five copies of the turret protein, which contains domains with both 7-N-methyltransferase and 2′-O-methyltransferase activities, and serves to catalyze the methylation reactions during RNA capping. Cypovirus of the family Reoviridae provides a good model system for studying the methylation reactions in dsRNA viruses. Here, we present the structure of a transcribing cypovirus to a resolution of ~ 3.8 Å by cryo-electron microscopy. The binding sites for both S-adenosyl-l-methionine and RNA in the two methyltransferases of the turret were identified. Structural analysis of the turret in complex with RNA revealed a pathway through which the RNA molecule reaches the active sites of the two methyltransferases before it is released into the cytoplasm. The pathway shows that RNA capping reactions occur in the active sites of different turret protein monomers, suggesting that RNA capping requires concerted efforts by at least three turret protein monomers. Thus, the turret structure provides novel insights into the precise mechanisms of RNA methylation. Graphical Abstract The two active sites in methyltransferases (MTase) in a transcribing dsRNA virus. Highlights • Structure of methyltransferases (MTases) and RNA in a transcribing dsRNA virus. • S-Adenosyl-l-methionine/S-adenosyl-l-homocysteine was observed in the two MTases. • A pathway was identified through which RNA reaches active sites of the two MTase. • Methylation reactions require concerted efforts by turret protein monomers. |
| Databáze: | OpenAIRE |
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