Biological Assembly 1  

 3D View: Structure | 1D-3D View | Electron Density | Validation Report | Ligand Interaction

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 82.47 kDa 
• Atom Count: 6522 
• Modelled Residue Count: 730 
• Deposited Residue Count: 730 
• Unique protein chains: 1

1FN9

CRYSTAL STRUCTURE OF THE REOVIRUS OUTER CAPSID PROTEIN SIGMA 3

• PDB DOI: 10.2210/pdb1FN9/pdb

• Classification: VIRAL PROTEIN
• Organism(s): Reovirus sp.
• Expression System: Spodoptera frugiperda
• Mutation(s): No 


• Deposited: 2000-08-21 Released: 2001-03-14 
• Deposition Author(s): Olland, A.M., Jane-Valbuena, J., Schiff, L.A., Nibert, M.L., Harrison, S.C.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.80 Å
• R-Value Free: 0.195 
• R-Value Work: 0.169 

Literature

Structure of the reovirus outer capsid and dsRNA-binding protein sigma3 at 1.8 A resolution.

Olland, A.M., Jane-Valbuena, J., Schiff, L.A., Nibert, M.L., Harrison, S.C.

(2001) EMBO J 20: 979-989

• PubMed: 11230122 
• DOI: 10.1093/emboj/20.5.979
• Primary Citation of Related Structures:  
  1FN9


• PubMed Abstract: 
  

The crystallographically determined structure of the reovirus outer capsid protein sigma3 reveals a two-lobed structure organized around a long central helix. The smaller of the two lobes includes a CCHC zinc-binding site. Residues that vary between strains and serotypes lie mainly on one surface of the protein; residues on the opposite surface are conserved. From a fit of this model to a reconstruction of the whole virion from electron cryomicroscopy, we propose that each sigma3 subunit is positioned with the small lobe anchoring it to the protein mu1 on the surface of the virion, and the large lobe, the site of initial cleavages during entry-related proteolytic disassembly, protruding outwards. The surface containing variable residues faces solvent. The crystallographic asymmetric unit contains two sigma3 subunits, tightly associated as a dimer. One broad surface of the dimer has a positively charged surface patch, which extends across the dyad. In infected cells, sigma3 binds dsRNA and inhibits the interferon response. The location and extent of the positively charged surface patch suggest that the dimer is the RNA-binding form of sigma3.

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Organizational Affiliation: 

Program in Virology, Division of Medical Sciences, Harvard Medical School, Harvard University, Cambridge, MA 02138, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
OUTER-CAPSID PROTEIN SIGMA 3	A, B	365	Reovirus sp.	Mutation(s): 0
UniProt
Find proteins for P03527 (Reovirus type 3 (strain Dearing)) Explore P03527  Go to UniProtKB:  P03527

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
ZN	C [auth A], D [auth B]	ZINC ION Zn PTFCDOFLOPIGGS-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.80 Å
• R-Value Free: 0.195 
• R-Value Work: 0.169 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 77.898	α = 90
b = 82.564	β = 90
c = 132.264	γ = 90

Software Package:

Software Name	Purpose
MLPHARE	phasing
CNS	refinement
DENZO	data reduction
SCALEPACK	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2000-08-21 
• Released Date: 2001-03-14 
Deposition Author(s): Olland, A.M., Jane-Valbuena, J., Schiff, L.A., Nibert, M.L., Harrison, S.C.

Revision History  

• Version 1.0: 2001-03-14
  Type: Initial release
  
• Version 1.1: 2008-04-27
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance