| Abstract: | A series of permuted variants of antigenomic HDV ribozyme and trans‐acting variants were constructed. The catalytic activity study of the ribozymes has shown that all the variants were capable of self‐cleaving with equally biphasic kinetics. Ribonuclease and Fe(II)‐EDTA cleavage have provided evidence that all designed ribozymes fold according to the pseudoknot model and the conformations of the initial and cleaved ribozyme are different. A scheme of HDV ribozyme self‐cleavage reaction was suggested. The role of hydrogen bonds in the reaction was evaluated by substitution of ribose in the ribozyme for deoxyribose. It was found that the 2′‐OH group of U23 and C27 is critical for the reaction to occur; the 2′‐OH group of U32 and U39 is important, while 2′‐OH groups of other nucleotides of loop 3, stem 4 and stem 1 are unimportant for the cleavage activity. |
