Alpha-DNA, a single-stranded secondary structure stabilized by ionic and hydrogen bonds: d(A(+)-G)n.
Alpha-DNA, a single-stranded secondary structure stabilized by ionic and hydrogen bonds: d(A(+)-G)n.
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Alpha-DNA，一种由离子键和氢键稳定的单链二级结构：d(A( )-G)n。
DOI：
10.1021/bi00044a005
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发表时间：
1995
期刊：
影响因子：
2.9
通讯作者：
Fresco,JR
中科院分区：
文献类型：
--
作者：
Shiber,MC;Lavelle,L;Fossella,JA;Fresco,JR
摘要：一种新的核酸二级结构，以d（A+-G）10为例，是由分子内的、协同的、酸诱导的卷曲-螺旋转变形成的。螺旋是明显左手的，缺乏碱基堆叠和配对，并通过dA+“侧链”残基（具有正电氢-NeH 2，-Ni+ H）和磷酸二酯骨架之间的氢键和离子键维持。建模表明，这些dA+残基大致平行于螺旋轴，与n- 1骨架磷酸（带负电氧）相互作用，有点像蛋白质α-螺旋中的-C = 0*~ H-N-纵向相互作用。此外，插入的dG侧链残基是螺旋外的，α-螺旋的氨基酸侧链也是如此。这样的堆叠出现在单链中、由单链形成的发夹的碱基对中、双链复合物的碱基对中、三链结构的碱基三联体中以及四链复合物的碱基四联体中。
Revised Manuscript Received July 3, 1995® abstract: A novel nucleic acid secondary structure, exemplified by d (A+-G) io, is formed by an intramolecular, cooperative, acid-induced, coil—helix transition. The helix is apparentlyleft-handed, lacks base stacking and pairing, and is maintained by hydrogen and ionic bonds between dA+“sidechain” residues (with electropositive hydrogens—NeH2,—Ni+ H) and the phosphodiester backbone. Modeling indicates that those dA+ residues lie approximately parallel to the helix axis, interacting with the n— 1 backbone phosphates (with electronegative oxygens), somewhat like the—C= 0*~ H—N—longitudinal interactions in a protein a-helix. Moreover, the intervening dG side-chain residues are extrahelical, as are amino acid side chains of an a-helix.All currently recognized types of nucleic acid secondary structure involve helical stacks of bases. Such stacks occur in single strands, in base pairs of hairpins formed by single strands, in base pairs of two-stranded complexes, in base triplets of three-stranded structures, and in base quartets of four-stranded complexes.