Chiroptical, ESMS and NMR spectroscopic study of the interaction of enantiopure lanthanide complexes with selected self-complementary dodecamer oligonucleotides
Chiroptical, ESMS and NMR spectroscopic study of the interaction of enantiopure lanthanide complexes with selected self-complementary dodecamer oligonucleotides
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DOI：
10.1039/b104796p
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发表时间：
2001-09-01
期刊：
影响因子：
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通讯作者：
Geraldes, CFGC
中科院分区：
文献类型：
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作者：
Bobba, G;Dickins, RS;Geraldes, CFGC
用ESMS、H-1 NMR、吸收光谱、差圆二色性、荧光猝灭和Ln发光光谱研究了带有N-甲基菲啶生色团的Eu和Yb的δ-和λ-阳离子配合物与[（CG）（6）]（2）、[（AT）（6）]和[CGCGAATTCGCG]（2）的相互作用。如吸收测量和非共价双链体加合物的直接ESMS观察所示，[（CG）（6）]（2）以高达3：1的极限化学计量和[CGCGAATTCGCG]（2）以高达2：1的极限化学计量发生逐步络合。与[（CG），]的结合发生时，对δ-Eu异构体的亲和力为8.7 × 10（6）M-1双链体（-1），比与[（AT）（6）]的亲和力大50倍（2）.结合的自由能的主要组成部分已被链接到嵌入相互作用，支持吸收，ICD和荧光猝灭特性：镧系元素配位。环境和局部螺旋度保持不变，但寡核苷酸在局部螺旋度和螺距方面经历了独特的变化，这对Ln络合物的手性敏感，在某些情况下对Ln离子的性质敏感（Yb对Eu）。用[CGCGAATTCGCG]（2）在增加浓度的Gd类似物存在下的H-1 NMR TOCSY和NOESY分析显示，最亲合的复合物结合位点位于寡核苷酸的中心，其中δ-异构体结合更强。
The interaction of Delta- and Lambda -Eu and Yb cationic complexes bearing an N-methylphenanthridinium chromophore with [(CG)(6)](2), [(AT)(6)], and [CGCGAATTCGCG](2) has been interrogated by ESMS, H-1 NMR, absorption, difference circular dichroism, fluorescence quenching and Ln luminescence emission spectroscopy. Stepwise complexation occurs with up to 3:1 limiting stoichiometry for [(CG)(6)](2) and 2:1 for [CGCGAATTCGCG](2), as indicated by absorption measurements and direct ESMS observation of the non-covalent duplex adducts. Binding to [(CG),], occurred with an affinity of 8.7 x 10(6) M-1 duplex(-1) for the Delta -Eu isomer which was 50 times greater than to [(AT)(6)](2). A primary component of the free energy of binding has been linked to an intercalative interaction, supported by absorption, ICD and fluorescence quenching characteristics: The lanthanide coordination. environment and local helicity remain unchanged but the oligonucleotide underwent distinctive changes in local helicity and pitch which were sensitive to the handedness of the Ln complex and in certain cases to the nature of the Ln ion (Yb vs. Eu). With [CGCGAATTCGCG](2) H-1 NMR TOCSY and NOESY analysis in the presence of increasing concentrations of the Gd analogues revealed that the most avid complex binding site was located in the centre of the oligonucleotide, with the Delta -isomer binding more strongly.