2AZ0

Flock House virus B2-dsRNA Complex (P212121)

• PDB DOI: https://doi.org/10.2210/pdb2AZ0/pdb
• NAKB: 2AZ0

• Classification: Viral protein/RNA
• Organism(s): Flock House virus
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2005-09-09 Released: 2005-10-11 
• Deposition Author(s): Chao, J.A., Lee, J.H., Chapados, B.R., Debler, E.W., Schneemann, A., Williamson, J.R.

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.60 Å
• R-Value Free: 0.269 
• R-Value Work: 0.241 
• R-Value Observed: 0.242 

Literature

Dual modes of RNA-silencing suppression by Flock House virus protein B2.

Chao, J.A., Lee, J.H., Chapados, B.R., Debler, E.W., Schneemann, A., Williamson, J.R.

(2005) Nat Struct Mol Biol 12: 952-957

• PubMed: 16228003 
• DOI: https://doi.org/10.1038/nsmb1005
• Primary Citation of Related Structures:  
  2AZ0, 2AZ2


• PubMed Abstract: 
  

  As a counter-defense against antiviral RNA silencing during infection, the insect Flock House virus (FHV) expresses the silencing suppressor protein B2. Biochemical experiments show that B2 binds to double-stranded RNA (dsRNA) without regard to length and inhibits cleavage of dsRNA by Dicer in vitro. A cocrystal structure reveals that a B2 dimer forms a four-helix bundle that binds to one face of an A-form RNA duplex independently of sequence. These results suggest that B2 blocks both cleavage of the FHV genome by Dicer and incorporation of FHV small interfering RNAs into the RNA-induced silencing complex.

---

Organizational Affiliation: 

Department of Molecular Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, California 92037, USA.

Biological Assembly 1  

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

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 28.07 kDa 
• Atom Count: 1,872 
• Modelled Residue Count: 177 
• Deposited Residue Count: 182 
• Unique protein chains: 1
• Unique nucleic acid chains: 1

Macromolecules

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
B2 protein	C [auth A], D [auth B]	73	Flock House virus	Mutation(s): 0  Gene Names: B2
UniProt
Find proteins for P68831 (Flock house virus) Explore P68831  Go to UniProtKB:  P68831

Entity ID: 1
Molecule	Chains	Length	Organism	Image
5'-R(*GP*CP*AP*(5BU)P*GP*GP*AP*CP*GP*CP*GP*(5BU)P*CP*CP*AP*(5BU)P*GP*C)-3'	A [auth C], B [auth D]	18	N/A

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.60 Å
• R-Value Free: 0.269 
• R-Value Work: 0.241 
• R-Value Observed: 0.242 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 50.261	α = 90
b = 86.232	β = 90
c = 94.338	γ = 90

Software Package:

Software Name	Purpose
MOSFLM	data reduction
SCALA	data scaling
PHASER	phasing
CNS	refinement
CCP4	data scaling

Structure Validation

Entry History 

Deposition Data

• Released Date: 2005-10-11 
Deposition Author(s): Chao, J.A., Lee, J.H., Chapados, B.R., Debler, E.W., Schneemann, A., Williamson, J.R.

Revision History  

• Version 1.0: 2005-10-11
  Type: Initial release
  
• Version 1.1: 2008-05-01
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2024-02-14
  Changes: Data collection, Database references, Derived calculations