• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Metal-ion-dependent folding of a uranyl-specific DNAzyme: Insight into function from fluorescence resonance energy transfer studies
【24h】

Metal-ion-dependent folding of a uranyl-specific DNAzyme: Insight into function from fluorescence resonance energy transfer studies

机译：铀酰特异性DNAzyme的金属离子依赖性折叠：荧光共振能量转移研究对功能的洞察

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

Fluorescence resonance energy transfer (FRET) has been used to study the global folding of an uranyl (UO_2~(2+))-specific 39E DNAzyme in the presence of Mg~(2+), Zn~(2+), Pb~(2+), or UO _2~(2+). At pH 5.5 and physiological ionic strength (100 mM Na~+), two of the three stems in this DNAzyme folded into a compact structure in the presence of Mg~(2+) or Zn~(2+). However, no folding occurred in the presence of Pb~(2+) or UO_2~(2+); this is analogous to the "lock-and-key" catalysis mode first observed in the Pb~(2+)-specific 8-17 DNAzyme. However, Mg ~(2+) and Zn~(2+) exert different effects on the 8-17 and 39E DNAzymes. Whereas Mg~(2+) or Zn~(2+)-dependent folding promoted 8-17 DNAzyme activity, the 39E DNAzyme folding induced by Mg~(2+) or Zn~(2+) inhibited UO_2~(2+)-specific activity. Group IIA series of metal ions (Mg~(2+), Ca~(2+), Sr~(2+)) also caused global folding of the 39E DNAzyme, for which the apparent binding affinity between these metal ions and the DNAzyme decreases as the ionic radius of the metal ions increases. Because the ionic radius of Sr~(2+) (1.12 ?) is comparable to that of Pb~(2+) (1.20 ?), but contrary to Pb~(2+), Sr~(2+) induces the DNAzyme to fold under identical conditions, ionic size alone cannot account for the unique folding behaviors induced by Pb~(2+) and UO_2~(2+). Under low ionic strength (30 mM Na~+), all four metal ions (Mg~(2+), Zn ~(2+), Pb~(2+), and UO_2~(2+)), caused 39E DNAzyme folding, suggesting that metal ions can neutralize the negative charge of DNA-backbone phosphates in addition to playing specific catalytic roles. Mg~(2+) at low (<2 mM) concentration promoted UO_2~(2+)-specific activity, whereas Mg~(2+) at high (>2 mM) concentration inhibited the UO_2~(2+)-specific activity. Therefore, the lock-and-key mode of DNAzymes depends on ionic strength, and the 39E DNAzyme is in the lock-and-key mode only at ionic strengths of 100 mM or greater.
机译：荧光共振能量转移（FRET）已用于研究在Mg〜（2 +），Zn〜（2 +），Pb〜存在下铀酰（UO_2〜（2+））特异性39E DNAzyme的整体折叠（2+）或UO _2〜（2+）。在pH 5.5和生理离子强度（100 mM Na〜+）下，该DNA酶的三个茎中的两个在Mg〜（2+）或Zn〜（2+）存在下折叠成紧凑结构。然而，在Pb〜（2+）或UO_2〜（2+）存在下没有发生折叠。这类似于在Pb〜（2+）特异的8-17 DNAzyme中首次观察到的“锁钥”催化模式。然而，Mg〜（2+）和Zn〜（2+）对8-17和39E DNAzyme的作用不同。 Mg〜（2+）或Zn〜（2+）依赖性折叠促进8-17 DNAzyme活性，而Mg〜（2+）或Zn〜（2+）诱导的39E DNAzyme折叠抑制UO_2〜（2+）特定的活动。 IIA组的一系列金属离子（Mg〜（2 +），Ca〜（2 +），Sr〜（2+））也引起39E DNAzyme的整体折叠，这些金属离子与DNAzyme之间的表观结合亲和力随金属离子的离子半径增加而减小。因为Sr〜（2+）（1.12？）的离子半径与Pb〜（2+）（1.20？）相当，但与Pb〜（2+）相反，Sr〜（2+）诱导了DNAzyme。在相同条件下折叠时，仅离子尺寸不能解释Pb〜（2+）和UO_2〜（2+）引起的独特折叠行为。在低离子强度（30 mM Na〜+）下，所有四种金属离子（Mg〜（2 +），Zn〜（2 +），Pb〜（2+）和UO_2〜（2+））引起39E DNAzyme折叠，表明金属离子除了起特定的催化作用外，还可以中和DNA骨干磷酸的负电荷。低（<2 mM）浓度的Mg〜（2+）促进UO_2〜（2+）特异性活性，而高（> 2 mM）浓度的Mg〜（2+）抑制UO_2〜（2+）特异性活性活动。因此，DNAzyme的锁定键模式取决于离子强度，并且39E DNAzyme仅在离子强度为100 mM或更高时才处于锁定键模式。

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