Kinetic parameters of hydrolysis of CpA and UpA sequences in an oligoribonucleotide by compounds functionally mimicking ribonuclease a
Beloglazova, N.G.; Mironova, N.L.; Konevets, D.A.; Petiuk, V.A.; Sil'nikov, V.N.; Vlasov, V.V.; Zenkova, M.A.
Molekuliarnaia Biologiia 36(6): 1068-1073
2002
ISSN/ISBN: 0026-8984 PMID: 12500546 Document Number: 547123
Kinetic parameters of cleavage of CpA and UpA sequences in an oligoribonucleotide under the action of artificial ribonuclease ABL3C1 were measured. The compounds were built of RNA-binding domain B, catalytic fragment C, linker L3 comprising 3 methylene groups, and aliphatic fragment A. The rate of cleavage of phosphodiester bonds in CpA sequence within decaribonucleotide UUCAUGUAAA was shown to be 3.4 +/- 0.2 times higher than in UpA sequence. The rate of cleavage of phosphodiester bonds were found to depend on substrate length: a thousandfold increase in cleavage rate constant was observed for CpA sequence in decaribonucleotide as compared with diribonucleotide monophosphate CpA. A slight decrease in the cleavage rates was observed for the reactions proceeding in different buffers at pH 7.0: imidazole > HEPES > phosphate > cacodylate. At the same time, the ratio of cleavage rates for CpA and UpA sequences remained constant.