It has previously been demonstrated by other workers that the duplex of a synthetic DNA poly(amino2dA-dT) undergoes a salt-induced conformational isomerization. We show in the present work using circular dichroism that the same isomerization is induced in poly(amino2dA-dT) by various alcohols. The isomerization was originally identified as the B-to-Z and then B-to-A conformational transition of DNA but we demonstrate that the high-salt or alcohol conformation of poly (amino2dA-dT) is the non Z-DNA zig-zag double helix we have previously observed with poly(dA-dT) and called X-DNA. X-DNA is a cesium cation specific conformation of poly(dA-dT) while no similar cation specificity is observed with poly(amino2dA-dT). Thus it appears that the extra amino group attached to A and cesium cations make the same thing; they probably dehydrate the double helix minor groove and relieve its conformational variability. Poly(amino2dA-dT) is exceptionally stable in X-DNA and conditions inducing it are mild, which opens the door to assess its molecular structure.

Institute of Biophysics Czechoslovak Academy of Sciences Brno

Zobrazit více v PubMed

J Mol Biol. 1974 Aug 25;87(4):817-33 PubMed

J Mol Biol. 1964 Oct;10:73-88 PubMed

Biopolymers. 1975 Mar;14(3):487-98 PubMed

Biopolymers. 1968;6(9):1345-53 PubMed

J Mol Biol. 1972 Jun 28;67(3):375-96 PubMed

Biopolymers. 1979 Apr;18(4):1009-19 PubMed

J Mol Biol. 1980 Oct 15;143(1):49-72 PubMed

Nucleic Acids Res. 1981 Sep 25;9(18):4783-98 PubMed

Proc Natl Acad Sci U S A. 1981 Aug;78(8):4801-4 PubMed

Nucleic Acids Res. 1982 Feb 11;10(3):1081-91 PubMed

J Mol Biol. 1981 Sep 25;151(3):535-56 PubMed

Nucleic Acids Res. 1982 Jul 24;10(14):4351-61 PubMed

Nucleic Acids Res. 1982 Nov 11;10(21):6969-79 PubMed

J Mol Biol. 1983 May 5;166(1):85-92 PubMed

Biopolymers. 1984 Jan;23(1):1-4 PubMed

Biochem Biophys Res Commun. 1984 Feb 14;118(3):848-53 PubMed

Biochim Biophys Acta. 1985 Feb 15;838(2):244-51 PubMed

Biochemistry. 1984 Dec 18;23(26):6723-32 PubMed

Biochemistry. 1985 Dec 3;24(25):7456-62 PubMed

Biochemistry. 1986 Jan 14;25(1):41-50 PubMed

Nucleic Acids Res. 1986 Mar 25;14(6):2737-48 PubMed

Nucleic Acids Res. 1986 Apr 25;14(8):3449-62 PubMed

Biochemistry. 1986 Nov 18;25(23):7464-70 PubMed

J Biomol Struct Dyn. 1985 Aug;3(1):43-55 PubMed

J Biomol Struct Dyn. 1985 Aug;3(1):67-83 PubMed

J Biomol Struct Dyn. 1983 Oct;1(1):21-57 PubMed

FEBS Lett. 1975 Mar 1;51(1):38-42 PubMed

Circular dichroism and conformational polymorphism of DNA

Transitions of poly(dI-dC), poly(dI-methyl5dC) and poly(dI-bromo5dC) among and within the B-, Z-, A- and X-DNA families of conformations