Komatsu Y, Yamashita S, Kazama N, Ohtsuka E
Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Nucleic Acids Symp Ser. 1999(42):279-80. doi: 10.1093/nass/42.1.279.
A new type of hammerhead ribozyme, with cleavage activity enhanced by oligonucleotides, was constructed. Stem II of the ribozyme was substituted with a non complementary loop (loop II). The modified ribozyme exhibited negligible cleavage of a target RNA; however, it was converted to an active molecule in the presence of oligonucleotides which were complementary to loop II. The oligonucleotide compensated for the disabled stem II by binding with the ribozyme. The induction of the cleavage activity was sequence-specific and the oligonucleotides containing a purine base as the 3'-dangling end were able to induce the cleavage activity of the ribozyme most efficiently. A photo-crosslinking experiment proved that a pseudo-half-knot structure was formed in the active molecule. The cleavage of two kinds of substrate RNAs with different sequences was controlled by the corresponding ribozymes activated by specific oligonucleotides.
构建了一种新型的锤头状核酶，其切割活性通过寡核苷酸得到增强。该核酶的茎II被非互补环（环II）取代。修饰后的核酶对靶RNA的切割作用可忽略不计；然而，在与环II互补的寡核苷酸存在的情况下，它会转变为活性分子。寡核苷酸通过与核酶结合来补偿失活的茎II。切割活性的诱导具有序列特异性，以嘌呤碱基作为3' - 悬垂端的寡核苷酸能够最有效地诱导核酶的切割活性。光交联实验证明活性分子中形成了假半结结构。两种不同序列的底物RNA的切割由特定寡核苷酸激活的相应核酶控制。
