3 SMALL RIBOOLIGONUCLEOTIDES WITH SPECIFIC ARGININE SITES

Arginine-binding RNA motifs are important to protein-RNA interaction a n perhaps also for Archean biochemistry. Selection-amplification was u sed to isolate three RNAs that are eluted by free arginine from an L-a rginine affinity column (K(d) almost-equal-to 0.2-0.4 mM). The binding sites contain specific internal and bulge loops, whose sequences can include arginine coding triplets. Binding is highly specific for argin ine, but all three motifs, like the self-splicing group I intron, also bind guanosine 5'-monophosphate. One site is stereoselective, somewha t preferring D-arginine.