Use of RNA-bound Tb3+ as a FRET donor

Lanthanide ions such as Tb3+ and Eu3+ have long been used to probe RNA and protein structures due to their luminescence properties and their steric and chemical similarities to biological metal ions such as Mg2+ and Ca2+. In this article, we introduce a method that utilizes the enhanced Tb3+ luminescence upon site-binding to RNA molecules as a FRET donor. Using this method, it is possible to identify specific metal ion-binding locations within a folded RNA molecule. Applications of this method include introducing FRET donors into molecules of interest by engineering RNA loops or bulges as Tb3+-binding pockets.