8TL1

Structure of Orthoreovirus RNA Chaperone SigmaNS N17


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.16 Å
  • R-Value Free: 0.251 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.211 

Starting Model: experimental
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This is version 1.1 of the entry. See complete history


Literature

Structure of orthoreovirus RNA chaperone sigma NS, a component of viral replication factories.

Zhao, B.Hu, L.Kaundal, S.Neetu, N.Lee, C.H.Somoulay, X.Sankaran, B.Taylor, G.M.Dermody, T.S.Venkataram Prasad, B.V.

(2024) Nat Commun 15: 2460-2460

  • DOI: https://doi.org/10.1038/s41467-024-46627-8
  • Primary Citation of Related Structures:  
    8TKA, 8TL1, 8TL8

  • PubMed Abstract: 

    The mammalian orthoreovirus (reovirus) σNS protein is required for formation of replication compartments that support viral genome replication and capsid assembly. Despite its functional importance, a mechanistic understanding of σNS is lacking. We conducted structural and biochemical analyses of a σNS mutant that forms dimers instead of the higher-order oligomers formed by wildtype (WT) σNS. The crystal structure shows that dimers interact with each other using N-terminal arms to form a helical assembly resembling WT σNS filaments in complex with RNA observed using cryo-EM. The interior of the helical assembly is of appropriate diameter to bind RNA. The helical assembly is disrupted by bile acids, which bind to the same site as the N-terminal arm. This finding suggests that the N-terminal arm functions in conferring context-dependent oligomeric states of σNS, which is supported by the structure of σNS lacking an N-terminal arm. We further observed that σNS has RNA chaperone activity likely essential for presenting mRNA to the viral polymerase for genome replication. This activity is reduced by bile acids and abolished by N-terminal arm deletion, suggesting that the activity requires formation of σNS oligomers. Our studies provide structural and mechanistic insights into the function of σNS in reovirus replication.


  • Organizational Affiliation

    Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Protein sigma-NS349OrthoreovirusMutation(s): 0 
Gene Names: S3
UniProt
Find proteins for P03526 (Reovirus type 3 (strain Dearing))
Explore P03526 
Go to UniProtKB:  P03526
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP03526
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.16 Å
  • R-Value Free: 0.251 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.211 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 77.522α = 90
b = 76.801β = 94.27
c = 89.09γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
HKL-2000data reduction
HKL-2000data scaling
MOLREPphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Other governmentUnited StatesR01 AI032539

Revision History  (Full details and data files)

  • Version 1.0: 2024-03-06
    Type: Initial release
  • Version 1.1: 2024-04-03
    Changes: Database references