Structure of the RNA-binding domain of Nodamura virus protein B2, a suppressor of RNA interference.

Protein B2 from Nodamura virus (NMV B2), a member of the Nodavirus family, acts as a suppressor of RNA interference (RNAi). The N-terminal domain of NMV B2, consisting of residues 1-79, recognizes double-stranded RNA (dsRNA). The 2.5 A crystal structure of the RNA-binding domain of NMV B2 shows a dimeric, helical bundle structure. The structure shows a conserved set of RNA-binding residues compared with flock house virus B2, despite limited sequence identity. The crystal packing places the RNA-binding residues along one face of symmetry-related molecules, suggesting a potential platform for recognition of dsRNA.