Enhancement of RNA self‐cleavage by micellar catalysis

FEBS Letters

Beier, Hildburg¹  Gross, Hans J¹  Riepe, Andrea¹ 

[1] Institut für Biochemie, Bayerische Julius-Maximilians-Universität, Biozentrum, Am Hubland, D-97074 Würzburg, Germany

关键词: Bulge loop;    Metal ion;    Micellar catalysis;    Monovalent cation;    Non-ionic detergent;    RNA self-cleavage;   

DOI  :  10.1016/S0014-5793(99)01038-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

It has been reported recently that naturally occurring catalytic RNAs like hammerhead and hairpin ribozyme do not require metal ions for efficient catalysis. It seems that the folded tertiary structure of the RNA contributes more to the catalytic function than was initially recognized. We found that a highly specific self-cleavage reaction can occur within a small bulge loop of four nucleotides in a mini-substrate derived from Arabidopsis thaliana intron-containing pre-tRNA^Tyr in the absence of metal ions. NH₄ ⁺ cations and non-ionic or zwitter-ionic detergents at or above their critical micelle concentration are sufficient to catalyze this reaction. The dependence on micelles for the reaction leads to the assumption that physical properties, i.e. the hydrophobic interior of a micelle, are essential for this self-cleavage reaction. We suggest that NH₄ ⁺-ions play a crucial role for the entry of the negatively charged RNA into the hydrophobic interior of a detergent micelle. A change of the pattern of hydration or hydrogen bonds caused by the hydrophobic surrounding enhances the reaction by a factor of 100. These findings suggest that highly structured RNAs may shift pK _a values towards neutrality via the local environment and thereby enhance their ability to perform general acid-base catalysis without the participation of metal ions.

【 授权许可】

Unknown