Crystallization and preliminary crystallographic analysis of a viral RNA-silencing suppressor encoded by Wuhan nodavirus

Wuhan nodavirus (WhNV), which is a new member of the Nodaviridae family, encodes a viral protein, B2, that suppresses RNA silencing and host-cell RNA interference (RNAi)-mediated immunity. Although Flock House virus (FHV), another member of the Nodaviridae family, also produces a B2 protein with a similar function, the primary sequences of the B2 proteins from WhNV and FHV have no similarity. To gain a better understanding of the structural details and the mechanism of suppression of RNA silencing by WhNV B2 and to compare it with FHV B2, recombinant WhNV B2 protein has been overexpressed in Escherichia coli, purified and crystallized at 291 K using PEG 4000 as a precipitant. A 2.8 Å resolution data set has been collected from a single crystal at 100 K. This crystal belonged to space group P2₁2₁2₁, with unit-cell parameters a = 27.3, b = 45.6, c = 133.9 Å, α = β = γ = 90°. Assuming the presence of two molecules in the asymmetric unit, the Matthews coefficient is 2.2 ų Da⁻¹.