Complexes of oligo(poly)nucleotides with structural anomalies

Peculiarities of recognition of CCA/TGG sequences in DNA by restriction endonucleases MvaI and EcoRII

“…Several of the DNA duplexes constructed (1, Id, l e , 2, 3-3c, 4-4c, 4f, 4h, 4m, 4n) have been characterized in this respect by UV spectroscopy and by circular dichroism (Dolinnaya et al, 1988;Gromova et al, 1984;Kubareva et al, 1990Kubareva et al, , 1991Kuznetsova et al, 1987bKuznetsova et al, , 1988. Summarizing these results with the data obtained from melting, circular dichroism, NMR and the X-ray structure of double-stranded oligonucleotides differing in primary structure from the compounds used here (Table 1) but carrying analogous point modifications (Delepierre et al, 1986;Delort et al, 1985;Diekmann and McLaughlin, 1988;Dolinnaya et al, 1986;Dolinnaya and Gryaznova, 1989;Frederick et al, 1988;Hunter et al, 1986;Kremer et al, 1987;Pieters et al, 1989;Purmal et al, 1984;Snowden-Ifft and Wemmer, 1990;Wang et al, 1982), one can arrive at the following conclusions.…”

“…Summarizing these results with the data obtained from melting, circular dichroism, NMR and the X-ray structure of double-stranded oligonucleotides differing in primary structure from the compounds used here (Table 1) but carrying analogous point modifications (Delepierre et al, 1986;Delort et al, 1985;Diekmann and McLaughlin, 1988;Dolinnaya et al, 1986;Dolinnaya and Gryaznova, 1989;Frederick et al, 1988;Hunter et al, 1986;Kremer et al, 1987;Pieters et al, 1989;Purmal et al, 1984;Snowden-Ifft and Wemmer, 1990;Wang et al, 1982), one can arrive at the following conclusions.…”

“…Other modifications-mismatched base pairs (Id, l e , 3b, 3c, 4k) (Dolinnaya et al, 1988;Dolinnaya and Gryaznova, 1989;Gromova et al, 1984), nucleoside analogues m6A, m4C, I (4b, 4f-4h) (Kubareva et al, 1990), single-strand breaks, nucleotide deletions or non-nucleotide insertions (2a-2f, 4m, 4n) (Dolinnaya and Gryaznova, 1989;Kuznetsova et al, 1988;Pieters et al, 1989;Snowden-Ifft and Wemmer, 1990) lower the melting temperatures of the duplexes. However, the destabilizing effect is not, as a rule, of great significance.…”

“…Modifications not hindering complementary iteractions and not affecting the conformatinal mobility of individual fragments of a molecule (la-lc, 3a, 4a, 4c-4e, 4i and 41) do not reduce the thermal stability of duplexes (Dolinnaya et al, 1986(Dolinnaya et al, , 1988Kuznetsova et al, 1987b). Other modifications-mismatched base pairs (Id, l e , 3b, 3c, 4k) (Dolinnaya et al, 1988;Dolinnaya and Gryaznova, 1989;Gromova et al, 1984), nucleoside analogues m6A, m4C, I (4b, 4f-4h) (Kubareva et al, 1990), single-strand breaks, nucleotide deletions or non-nucleotide insertions (2a-2f, 4m, 4n) (Dolinnaya and Gryaznova, 1989;Kuznetsova et al, 1988;Pieters et al, 1989;Snowden-Ifft and Wemmer, 1990) lower the melting temperatures of the duplexes. However, the destabilizing effect is not, as a rule, of great significance.…”

Elementary Molecular Mechanisms of the Spontaneous Point Mutations in DNA: A Novel Quantum-Chemical Insight into the Classical Understanding

“…In the plane-symmetric transition states of the amino group rotations TS 2 and TS 3 the -N bond becomes elongated, the N-H bonds become shortened and the valence angle H-N-H distinctly deviates from 120°, at that the amine fragment ≥C-NH 2 is highly pyramidalized as compared to the equilibrium configuration. All these results clearly demonstrate that the structural nonrigidity of nitrogenous bases is determined by intramolecular quantumchemical effect -p-π-conjugation of a lone electron pair (LEP) of the nitrogen atom of the amine fragment ≥C-NH 2 with the π-electronic system of the ring (Dolinnaya & Gromova, 1983;Dolinnaya & Gryaznova, 1989).…”