Changes in hydration of lanthanide ions on binding to DNA in aqueous solution
Changes in hydration of lanthanide ions on binding to DNA in aqueous solution
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DOI：
10.1021/la051493u
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发表时间：
2005-11-08
期刊：
影响因子：
3.9
通讯作者：
Miguel, MD
中科院分区：
文献类型：
--
作者：
Costa, D;Burrows, HD;Miguel, MD
用荧光光谱和衰减光谱研究了三价镧系元素Ce（III）、Eu（III）和Tb（III）与脱氧核糖核酸钠（DNA）在水溶液中的相互作用。与DNA的络合通过发光强度的变化来指示。在系统铽（III）-DNA，发光随pH值的变化，建议是由于磷酸基团的质子化。Tb（III）结合到DNA上的水合程度之后是在水和氧化氘溶液中的发光寿命测量，并且发现镧系元素离子在pH 4.7和pH 7下结合到长双链DNA上时失去至少一个水合水。而不同的行为上观察到的结合长或短的单链DNA，其中6个水分子丢失，独立的pH值。这表明，在这种情况下，镧系元素可能结合到DNA骨架的碱基。DNA构象似乎是结合的重要因素。此外，同位素对铽发光寿命的影响可能提供一种有用的方法来区分单链和双链DNA。DSC结果与在铽存在下在pH 9下DNA双螺旋的裂解一致。
The interaction of the trivalent lanthanides Ce(III), Eu(III), and Tb(III) with sodium deoxyribonucleic acid (DNA) in aqueous solution has been studied using their luminescence spectra and decays. Complexation with DNA is indicated by changes in luminescence intensity. In the system terbium(III)-DNA, changes in luminescence with pH are suggested to be due to the protonation of phosphate groups. The degree of hydration of Tb(III) on binding to DNA is followed by luminescence lifetime measurements in water and deuterium oxide solutions, and it is found that the lanthanide ion loses at least one hydration water on binding to long double stranded DNA at pH 4.7 and pH 7. Rather different behavior is observed on binding to long or short single stranded DNA, where six water molecules are lost, independent of pH. It is suggested that in this case the lanthanide probably binds to the bases of the DNA backbone. The DNA conformation seems to be an important factor in the binding. In addition, the isotopic effect on terbium luminescence lifetime may provide a useful method to distinguish between single and double stranded DNA. DSC results are consistent with cleavage of the double helix of DNA at pH 9 in the presence of terbium.