Russian Journal of Bioorganic Chemistry, Vol. 25, No. 10, 1999, đ . 639

Artificial Ribonucleases: 1. Synthesis and Properties of Conjugates Containing an RNA-binding Fragment with Lys Residues and an RNA-hydrolyzing Fragment with Imidazole Residue

N. S. Zhdan**, I. L. Kuznetsova**, A. V. Vlassov*, V. N. Sil’nikov*, 1 M. A. Zenkova*, and V. V. Vlassov*

*Novosibirsk Institute of Bioorganic Chemistry, Siberian Division, Russian Academy of Sciences, pr. akademika Lavrent’eva 8, Novosibirsk , 630090 Russia ** Novosibirsk State University , ul. Pirogova 2, Novosibirsk , 630090 Russia

Received December 25, 1998; in final form, April 13, 1999

Abstract: A series of RNA-hydrolyzing constructions was synthesized on the basis of peptide-like molecules containing residues of L-lysine, histamine and histidine methyl ester. These were shown to hydrolyze RNA effectively at neutral pH values. The in vitro transcript of tRNALys from human mitochondria and a tRNA-like fragment of RNA of Turnip Yellow Mosaic Virus were used in the experiments. Our chemical RNases quantitatively depolymerize some definite sequences (CA UA > CG UC, CC, or CU) in both RNA molecules under optimum conditions. Moreover, no other sites were affected and no statistical hydrolysis was observed even after prolonged RNA incubation with the compounds of this series. The depolymerization rate of the RNA substrates exhibits a complex dependence on the concentration of ions of monovalent metals and on the concentration of the artificial ribonucleases.

Key words: RNA hydrolysis, chemical nucleases, modeling of enzyme active sites

Russian Journal of Bioorganic Chemistry ,

Vol. 26, No. 9, 2000, đ . 610

Chemical Ribonucleases: 2. 1 Design and Hydrolytic Activity of the Ribonuclease Mimics on the Basis of Diazabicyclo[2.2.2]octane with a Differing Number of Positive Charges

M. A. Zenkova*, 2 A. V. Vlassov*, D. A. Konevets*, V. N. Silnikov*, R. Giege**, and V. V. Vlassov*

*Novosibirsk Institute of Bioorganic Chemistry, Siberian Division, Russian Academy of Sciences, prosp. Akad. Lavrentieva 8, Novosibirsk, 630090 Russia, **Instut de Biologie Moléculaire and Cellulaire, Starsbourg, France

Abstract: A procedure was proposed allowing one to synthesize RNA mimics on the basis of conjugates of diazabicyclo[2.2.2]octane with imidazole bearing a varying number of positive charges (nDm series, where n is the number of positive charges at neutral pH, m is the code of an imidazole-containing fragment of the catalytic domain: 1, histamine; 2, histidine methyl ester). The hydrolytic activity of six compounds of this series was studied in physiological conditions using in vitro transcript of human mitochondrial tRNALys as a substrate. It was shown that the rate of RNA hydrolysis with nDm conjugates rises with an increase in the number of positive charges: an approximately 30-fold acceleration of hydrolysis was observed with an increase in the total charge of the construct from +2 to +4.

Key words: artificial RNases; enzyme active site modeling; RNA, hydrolysis