Crystallization and preliminary X-ray diffraction analysis of the barley yellow dwarf virus cap-independent translation element

Barley yellow dwarf virus (BYDV) RNA lacks a 5′ m7GTP cap, yet it is translated efficiently because it contains a 105-base BYDV-like cap-independent translation element (BTE) in the 3′ untranslated region (UTR). To understand how the BTE outcompetes the host mRNA for protein-synthesis machinery, its three-dimensional structure is being determined at high resolution. The purification using transcription from DNA containing 2′-O-methyl nucleotides and preliminary crystallographic analyses of the BTE RNA are presented here. After varying the BTE sequence and crystallization-condition optimization, crystals were obtained that diffracted to below 5 Å resolution, with a complete data set being collected to 6.9 Å resolution. This crystal form indexes with an Rmerge of 0.094 in the monoclinic space group C2, with unit-cell parameters a = 316.6, b = 54.2, c = 114.5 Å, α = γ = 90, β = 105.1°