Fluorescence quenching properties of multiple pyrene-modified RNAs.

RNA molecules with multiple pyrenylmethyl substituents on the 2'-O-sugar residues can form duplexes with complementary RNA sequences without losing thermal stability. In the RNA duplexes, covalently incorporated pyrenes can assemble in a helical manner along the minor grooves of the duplex. These helically assembled pyrene arrays exhibit intense excimer emissions that are efficiently quenched with methyl viologen.