National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)
AI36040
米国
Welch Foundation
Q1279
米国
引用
ジャーナル: Sci Adv / 年: 2020 タイトル: 2.7 Å cryo-EM structure of rotavirus core protein VP3, a unique capping machine with a helicase activity. 著者: 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 / 要旨: 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.
根拠: gel filtration, Gel filtration profile indicates a tetrameric assembly in solution, equilibrium centrifugation, Analytical Ultracentrifugation confirms tetrameric state is preferred ...根拠: gel filtration, Gel filtration profile indicates a tetrameric assembly in solution, equilibrium centrifugation, Analytical Ultracentrifugation confirms tetrameric state is preferred oligomeric assembly in solution