...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >Evidence for Hoogsteen GC base pairs in the proton-induced transition from right-handed to left-handed poly(dG-dC).poly(dG-dC)
【24h】

Evidence for Hoogsteen GC base pairs in the proton-induced transition from right-handed to left-handed poly(dG-dC).poly(dG-dC)

机译：质子诱导的从右手向左手poly（dG-dC）.poly（dG-dC）过渡中的Hoogsteen GC碱基对的证据。

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The structure of double-helical poly(dG-dC).poly(dG-dC) is investigated at various pH values with Raman spectroscopy, absorption spectroscopy, and circular dichroism. A comparison is made between the B-form with Watson-Crick base pairing at 1 mM [Na+] and pH 7.2, the Z-form with Watson-Crick base pairing at 4 M [Na+] and pH 7.2, and a different structure at 1 mM [Na+] and pH 4.5 as well as at 150 mM [Na+] and pH 3.1. The CD spectrum of poly(dG-dC). poly(dG-dC) under the latter conditions does not show a negative band at 290 nm. The structure is a double-helical structure different from the B-form and the Z-form according to circular dichroism, Raman, and absorption spectroscopic studies. The Raman spectra evidence that the structure contains Hoogsteen base pairing. This can be accommodated in the double helix when the cytosine group is protonated and the sugar-guanine conformer has adopted a C2'-endo/syn conformation. It is shown that this antiparallel-stranded Hoogsteen base paired structure can be maintained under varying conditions, balancing the decrease in pH with an increased salt concentration. It is further concluded that the proton-induced transition from a Watson-Crick to a Hoogsteen base pair is aided by a decrease of [Na+] at pH 4.5 and occurs prior to a conversion from a right-handed helix to a left-handed helix.
机译：用拉曼光谱，吸收光谱和圆二色性研究了在各种pH值下双螺旋聚（dG-dC）。聚（dG-dC）的结构。比较了在1 mM [Na +]和pH 7.2下具有Watson-Crick碱基配对的B型，在4 M [Na +]和pH 7.2下具有Watson-Crick碱基配对的Z型和在1 mM [Na +]和pH 4.5，以及150 mM [Na +]和pH 3.1。聚（dG-dC）的CD光谱。在后一种条件下，聚（dG-dC）在290 nm处未显示负带。根据圆二色性，拉曼和吸收光谱研究，该结构是不同于B-形和Z-形的双螺旋结构。拉曼光谱证明该结构包含Hoogsteen碱基配对。当胞嘧啶基团被质子化并且糖-鸟嘌呤构象异构体采用C2'-endo / syn构象时，这可以容纳在双螺旋中。结果表明，这种反平行链Hoogsteen碱基配对结构可以在不同条件下保持，平衡pH的降低与盐浓度的增加。进一步得出结论，质子诱导的从沃森-克里克（Watson-Crick）到霍格斯汀（Hoogsteen）碱基对的转变是通过在pH 4.5时[Na +]降低而实现的，并且发生在从右手螺旋向左手螺旋转换之前。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号