BROMINATION STABILIZES POLY(DG-DC) IN THE Z-DNA FORM UNDER LOW-SALT CONDITIONS
BROMINATION STABILIZES POLY(DG-DC) IN THE Z-DNA FORM UNDER LOW-SALT CONDITIONS
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DOI：
10.1021/bi00296a009
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发表时间：
1984-01-01
期刊：
影响因子：
2.9
通讯作者：
RICH, A
中科院分区：
文献类型：
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作者：
MOLLER, A;NORDHEIM, A;RICH, A
Achim Móller、Alfred Nordheim、Sharon A. Kozlowski、Dinshaw J. Patel 和 Alexander Rich* 摘要：使用圆二色性研究，Pohl & Jovin (1972)[Pohl, F. M., & Jovin, T. M.(1972) J. Mol.生物。 67, 375-396]证明聚（dG-dC）经历以光谱反转为特征的盐依赖性构象变化。低盐形式对应于 DNA 的右手 B 形式，高盐形式对应于左手 Z-DNA 螺旋。通过在鸟嘌呤的 C8 位置和胞嘧啶残基的 C5 位置添加溴原子对聚 (dG-dC) 进行修饰，使该聚合物在低盐条件下以 Z-DNA 形式稳定。发现鸟嘌呤残基的反应性是胞嘧啶残基的两倍。经过38％Br8G和18％Br5C的修饰，聚合物在生理条件下形成稳定的Z-DNA螺旋。溴化产生的光谱特征与 4 M NaCl 中的聚 (dG-dC) 非常相似。然而，如溴化乙锭嵌入研究所示，溴化并没有冻结 Z 结构。染料的添加有利于间
Achim Móller, Alfred Nordheim, Sharon A. Kozlowski, Dinshaw J. Patel, and Alexander Rich* abstract: Using circular dichroism studies, Pohl & Jovin (1972)[Pohl, F. M., & Jovin, T. M.(1972) J. Mol. Biol. 67, 375-396] demonstrated that poly (dG-dC) undergoes a salt-dependent conformational change characterized by a spectral inversion. The low-saltform corresponds to the right-handed B form of DNA and the high-salt form to the left-handed Z-DNA helix. Modification of poly (dG-dC) by adding bromine atoms to the C8 position of guanine and the C5 position of cytosine residues stabilized this polymer in the Z-DNA form under low-salt conditions. The guanine residues were found to be twice as reactive as the cytosine residues. With a modification of 38% Br8G and 18% Br5C, the polymersformed a stable Z-DNA helixunder physiological conditions. The bromination produced spectroscopic features very similar to poly (dG-dC) in 4 M NaCl. However, bromination did not freeze the Z structure as was shown by ethidium bromide intercalation studies. Addition of the dye favored an inter-