Analysis of the Mechanism of Mg²⁺ Action on the RNase Activity of Serratia marcescens Endonuclease

© 2016, Springer Science+Business Media New York.The main goal of the investigation was to analyze the mechanism of Mg2+ action on the digestive activity of Serratia marcescens nuclease towards RNA due to the potential application of the nuclease as a reagent for removing nucleic acids from biomedical samples as well as an antiviral factor. Examination of the mechanism revealed that it was similar to the mechanism of the metals actions on the DNase activity. The optimal Mg2+ amount was linked with the changing secondary structure of RNA—substrates within A-helix. Addition of Mg2+ was found to affect both the rates of products dissociations from the enzyme-substrate complexes and the enzyme associations with the substrates, that was supported by strong increase in the Kcat values and change in the Km values. Comparing the mechanisms of Mg2+ action on RNase and DNase activities in S. marcescens nuclease, we identified a preference for DNA in the absence of Mg2+ that was supported with the Kcat values