[Identification of 2',3'-cGMP as an intermediate of RNA catalytic cleavage by binase and evaluation of its biological action]

Binase--Bacillus pumilus RNase--endonuclease cleaves the phosphodiester bond between the 3'-guanylic residue and the 5'-OH residue of adjacent nucleotides with the formation of corresponding intermediate 2',3'-cGMP. Subsequent hydrolysis of 2',3'-cGMP into 3'-phosphate is highly specific and occurs slowly So the question arises about the existing time of that positional isomer during RNA catalytic cleavage by binase and about 2',3'-cGMP role in antitumor activity of the enzyme: In present work by means of enzyme-linked immunosorbent assay we established that during catalytic cleavage of RNA by binase 2',3'-cGMP is preserved in reaction mixture for an hour, at the same time phosphodiesterases activation doesn't lead to the total elimination of 2',3'-cGMP. The highest amount of 2',3'-cGMP was observed under the pH 8.5, it reaches nanomolar concentration at initial RNA concentration of 100-1000 μg/mL. Exogenous 2',3'-cGMP, like its positional isomer 3',5'-cGMP, doesn't trigger an Apoptosis of human lung adenocarcinoma A549 cells, which are sensitive to binase apoptogenic action. Taking into account data about binase internalization and activation of mitochondrial pores opening by 2',3'-cyclic guanosine phosphates we may consider that 2',3'-cGMP can contribute to the Apoptosis initiated by binase only when 2',3'-cGMP is generated intracellularly.