Binding studies of cationic uridyl ribonucleic guanidine (RNG) to DNA

Replacement of the phosphodiester linkages of polyanionic RNA with guanidine linkers provides a polycationic ribonucleic guanidine (RNG). The pentameric uridyl RNG (RNG U5) was found to bind a pentameric adenyl DNA (DNA A5) with a 1:1 stoichiometry as determined by the method of continuous variation. This polycationic RNG binds with unprecedented affinity with the polyanionic DNA providing a double helix. This association of RNG and DNA is highly sequence specific. Thermal denaturation (Tm) studies establish that RNG is able to discriminate between complementary and noncomplementary bases. Results of the hybridization properties, sequence specificity, and the global conformation studies of the RNG U5•DNA A5 duplex are described.