A) Fluorescence spectrum of MGA upon binding 10 µM MG, λex = 630 nm. Dashed line, fluorescence of control RNA with 10 µM MG, B) Relative fluorescence yield from 10 µM MG interacting with MGA, 4xMGA and 8xMGA on a molar basis. Aptamer concentrations were 0.8, 0.2, and 0.08 µM respectively. C) Binding of MG to MGA, 4xMGA and 8xMGA (each normalized to the maximum fluorescence). D) Kds of MGA (1) 4xMGA (2) and 8xMGA (8) for MG.