Fig. 1From: R3D-BLAST2: an improved search tool for similar RNA 3D substructuresAn η- θ plot of all non-terminal nucleotides from a non-redundant list of 876 RNA 3D structures, where the intersection of perpendicular gray regions (150° ≤η≤ 190° and 190° ≤θ≤ 260°) is designated the helical regionBack to article page