Non-Enzymatic RNA Hydrolysis Promoted by the Combined Catalytic Activity of Buffers and Magnesium Ions

Although Mg2+ is an important cofactor for the specific degradation of RNA by ribozymes, it is not considered as a typical chemical nuclease. In this study we show that in combination with common buffers such as tris(hydroxymethyl)aminomethane and sodium borate, Mg2+ is a powerful catalyst for the degradation of RNA. pH and temperature are found to be the principal factors for the efficient degradation of RNA. Whereas in Tris-HCl/Mg2+ the efficient cleavage starts at pH values higher than 7.5 and temperatures higher than 37 degrees C, in sodium borate RNA degradation begins at pH 7.0 and at 37 degrees C. RNA hydrolysis promoted under the combined catalytic activity of buffer/Mg2+ results in partially degraded RNA and negligible amounts of acid-soluble material. Reaction is insensitive to the concentration of monovalent cations but is completely prevented by chelating agents (EDTA and citrate) at concentrations exceeding that of Mg2+. Borate-magnesium reaction is inhibited also by some polyvalent alcohols (glycerol) and sugars.