ハンマーヘッド型リボザイム : 金属イオン相互作用の分光学的解析

概要

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Biologically active RNA molecules utilize metal ions to fold into specific conformations or to form a catalytic center. Hammerhead ribozymes also contain a metal ion-binding motif in their conserved core region. This motif and bound metal ions have recently been focused on from the viewpoint of whether the metal ions are a catalytic metal or a structural metal. We studied the interaction between metal ions and an RNA oligomer, r(GGACGAGUCC), which mimics the metal ion-binding motif of hammerhead ribozymes, using NMR spectroscopy in solution. Using ^<15>N-labeled RNA oligomers, the chemical shift of N7 of the G7 residue [N7(G7)] in the metal ion-binding motif was specifically perturbed upon the addition of Cd(II). It was also found that the ^<31>P resonance of the phosphate of the A9 residue showed the largest perturbation of all the ^<31>P resonances during titration. These data indicate that divalent cations can bind to the metal ion-binding motif in solution, and that the binding sites for cations are N7 (G7) and the phosphate of A9. More importantly, the metal ion-binding motif is an independent functional module that can capture divalent cations without the assistance of other conserved residues in hammerhead ribozymes.
公益社団法人日本薬学会の論文
2003-05-01