NMR Structures of (rGC U GA G GCU) 2 and (rGC G GA U GCU) 2 :  Probing the Structural Features That Shape the Thermodynamic Stability of GA Pairs † , ‡

NMR Structures of (rGC U GA G GCU) 2 and (rGC G GA U GCU) 2 :  Probing the Structural Features That Shape the Thermodynamic Stability of GA Pairs † , ‡