Preferential activation of the 8-17 deoxyribozyme by Ca(2+) ions. Evidence for the identity of 8-17 with the catalytic domain of the Mg5 deoxyribozyme.

摘要: The 8-17 deoxyribozyme is a small RNA-cleaving DNA molecule of potential therapeutic interest. Here, the cleavage rates 16 variants were measured in presence different divalent metal ions. Despite fact that was originally selected vitro for activity Mg(2+) (Santoro, S. W., and Joyce, G. F. (1997) Proc. Natl. Acad. Sci. U. A. 94, 4262-4266) nearly all exhibited substantially higher (up to 20-fold) reaction Ca(2+) as compared with Mg(2+). This preference calcium ions critically depended on nucleoside residues at two specific positions core. specificity strongly reminiscent properties Mg5, an RNA phosphodiester-cleaving previously isolated by Faulhammer Famulok (Faulhammer, D., Famulok, M. (1996) Angew. Chem. Int. Ed. Engl. 35, 2837-2841). Indeed, analysis Mg5 sequence revealed complete motif, coincident conserved region Mg5. An modeled after displayed catalytic features comparable those reported full-length deoxyribozyme.