Morpholino oligonucleotides do not participate perfectly in standard Watson-Crick complexes with RNA

Inhibition by EGS, PMO, and PPMO on cleavage of wild-type CAT mRNA. (A) Cleavage of CAT mRNA substrate under competitive conditions. The amount of CAT^EGS was constant at 50 times the amount of mRNA at the top of the graph. The amount of EGS^PMO varied as indicated in the figure. Cleavage at the EGS or the PP site is indicated in the graph. (B) The amount of CAT^PMO was constant, as shown at the top of the graph, and the amount of EGS varied. Cleavage is at different sites, as indicated in the graph. (C) The same as in B except the CAT^PPMO EGS was constant. Assay conditions are in Materials and Methods.