PMID: 16228003 , Related PDB ids: 2AZ0, 2AZ2
Chao JA, Lee JH, Chapados BR, Debler EW, Schneemann A, Williamson JR
Dual modes of RNA-silencing suppression by Flock House virus protein B2.
Nat Struct Mol Biol. 2005 Nov;12(11):952-7.
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.