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-Structure paper
Title | 2.7 Å cryo-EM structure of rotavirus core protein VP3, a unique capping machine with a helicase activity. |
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Journal, issue, pages | Sci Adv, Vol. 6, Issue 16, Page eaay6410, Year 2020 |
Publish date | Apr 15, 2020 |
Authors | Dilip Kumar / Xinzhe Yu / Sue E Crawford / Rodolfo Moreno / Joanita Jakana / Banumathi Sankaran / Ramakrishnan Anish / Soni Kaundal / Liya Hu / Mary K Estes / Zhao Wang / B V Venkataram Prasad / |
PubMed Abstract | In many viruses, including rotavirus (RV), the major pathogen of infantile gastroenteritis, capping of viral messenger RNAs is a pivotal step for efficient translation of the viral genome. In RV, VP3 ...In many viruses, including rotavirus (RV), the major pathogen of infantile gastroenteritis, capping of viral messenger RNAs is a pivotal step for efficient translation of the viral genome. In RV, VP3 caps the nascent transcripts synthesized from the genomic dsRNA segments by the RV polymerase VP1 within the particle core. Here, from cryo-electron microscopy, x-ray crystallography, and biochemical analyses, we show that VP3 forms a stable tetrameric assembly with each subunit having a modular domain organization, which uniquely integrates five distinct enzymatic steps required for capping the transcripts. In addition to the previously known guanylyl- and methyltransferase activities, we show that VP3 exhibits hitherto unsuspected RNA triphosphatase activity necessary for initiating transcript capping and RNA helicase activity likely required for separating the RNA duplex formed transiently during endogenous transcription. From our studies, we propose a new mechanism for how VP3 inside the virion core caps the nascent transcripts exiting from the polymerase. |
External links | Sci Adv / PubMed:32494598 / PubMed Central |
Methods | EM (single particle) / X-ray diffraction |
Resolution | 3.5 - 11.8 Å |
Structure data | EMDB-20159: PDB-6o3v: |
Chemicals | ChemComp-5GP: ChemComp-EDO: ChemComp-SO4: ChemComp-HOH: |
Source |
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Keywords | STRUCTURAL PROTEIN / Rotavirus / VP3 / Capping enzyme / Guanylyl transferase / Methyl transferase / RTPase / PDE |