Properties of Antigenomic HDV Ribozyme Consisting of Two RNA Chains

B:LS ribozyme, a trans-variant of naturally occurring HDV ribozyme, has been constructed. The ribozyme consists of a substrate-containing LS chain and a catalytic B chain and differs from previously constructed trans-ribozymes in the length and nucleotide sequence of its oligonucleotide chains (33 and 34 bp, respectively). The chains readily associate with each other at room temperature, at which the LS cleavage reaction is negligible, which makes it possible to investigate association of the intact chains. At the same time, the self-cleavage rate constant for the trans-ribozyme B:LS at 50°C is close to those for the previously studied permuted cis-ribozymes, especially the LSB variant. In addition, the dependence of trans-ribozyme on reaction conditions (Mg²⁺ concentration, pH, and temperature) resembled that of cis-ribozyme. Similar to other trans-ribozymes, B:LS ribozyme demonstrated the ability for multiple turnover of the B strand with an excess of the substrate LS chain. The kinetic model of the self-cleavage reaction for B:LS is presented at http://www.cardio.ru/labgen/RZ_r.html. Taken together, our results show that the novel trans-variant of HDV ribozyme can be used as a model for analyzing the process of HDV ribozyme self-cleavage.