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Structural basis of rotavirus RNA chaperone displacement and RNA annealing.

Published version
Peer-reviewed

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Type

Article

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Authors

Bravo, Jack PK 
Venditti, Luca 
Gail, Emma H 

Abstract

Rotavirus genomes are distributed between 11 distinct RNA molecules, all of which must be selectively copackaged during virus assembly. This likely occurs through sequence-specific RNA interactions facilitated by the RNA chaperone NSP2. Here, we report that NSP2 autoregulates its chaperone activity through its C-terminal region (CTR) that promotes RNA-RNA interactions by limiting its helix-unwinding activity. Unexpectedly, structural proteomics data revealed that the CTR does not directly interact with RNA, while accelerating RNA release from NSP2. Cryo-electron microscopy reconstructions of an NSP2-RNA complex reveal a highly conserved acidic patch on the CTR, which is poised toward the bound RNA. Virus replication was abrogated by charge-disrupting mutations within the acidic patch but completely restored by charge-preserving mutations. Mechanistic similarities between NSP2 and the unrelated bacterial RNA chaperone Hfq suggest that accelerating RNA dissociation while promoting intermolecular RNA interactions may be a widespread strategy of RNA chaperone recycling.

Description

Keywords

RNA chaperones, genome assembly, ribonucleoproteins, rotavirus, Cryoelectron Microscopy, Genome, Viral, Models, Molecular, Molecular Chaperones, RNA Folding, RNA, Viral, RNA-Binding Proteins, Ribonucleoproteins, Rotavirus, Viral Genome Packaging, Viral Nonstructural Proteins

Journal Title

Proc Natl Acad Sci U S A

Conference Name

Journal ISSN

0027-8424
1091-6490

Volume Title

118

Publisher

Proceedings of the National Academy of Sciences