Ribbon representation of a single structure (from the ensemble calculated in solution by NMR) of the tandem zinc finger (TZF) domain of the protein TIS11d bound to the class II AU-rich element (ARE) from the 3'-untranslated region of mRNA. The protein backbone is shown in green, the RNA backbone in orange, and RNA bases in yellow. The location of the conserved R/KYKTEL motifs is shown in purple. Zinc ions are shown as gray spheres. The side chains of zinc ligands are shown in yellow (Cys) or blue (His). Aromatic rings that intercalate between the RNA bases are shown in red.