Cleavage of RNA by an amphiphilic compound lacking traditional catalytic groups

Recently, in experiments with combinatorial libraries of amphiphilic compounds lacking groups, known as catalysts of transesterification reaction, we discovered novel RNA-cleaving compounds [N. Kovalev, E. Burakova, V. Silnikov, M. Zenkova, V. Vlassov, Bioorg. Chem. 34 (2006) 274-286]. In the present study, we investigate cleavage of RNA by the most active representative of these libraries, compound named Dp12. Sequence-specificity of RNA cleavage and influence of reaction conditions on cleavage rate suggested that Dp12 enormously accelerates spontaneous RNA cleavage. Light scattering experiments revealed that the RNA cleavage proceeds within multiplexes formed by assembles of RNA and Dp12 molecules, at Dp12 concentration far below critical concentration of micelle formation. Under these conditions, Dp12 is presented in the solution as individual molecules, but addition of RNA to this solution triggers formation of the multiplexes. The obtained data suggest a possible mechanism of RNA cleavage, which includes interaction of the compound with RNA sugar-phosphate backbone resulting in changing of ribose conformation. This leads to juxtaposition of the 2'-hydroxyl group and internucleotide phosphorus atom at a distance needed for the transesterification to occur.