The structure of a tetrahydrofolate-sensing riboswitch reveals two ligand binding sites in a single aptamer.
Trausch JJ, Ceres P, Reyes FE, Batey RT. The structure of a tetrahydrofolate-sensing riboswitch reveals two ligand binding sites in a single aptamer. Structure. 2011 Oct 12; 19(10):1413-23.