Methods to detect and characterize metal ion binding sites in RNA.

Metal ions are inextricably associated with RNAs of any size and control their folding and activity to a large part. In order to understand RNA mechanisms, also the positioning, affinities and kinetics of metal ion binding must be known. Due to the spectroscopic silence and relatively fast exchange rates of the metal ions usually associated with RNAs, this task is extremely challenging and thus numerous methods have been developed and applied in the past. Here we provide an overview on the different metal ions and methods applied in RNA (bio)chemistry: The physical-chemical properties of important metal ions are presented and briefly discussed with respect to their application together with RNA. Each method ranging from spectroscopic over biochemical to computational approaches is briefly described also mentioning caveats that might occur during the experiment and/or interpretation of the results.