Lenz Tabea, Javornik Uroš, Hebenbrock Marian, Plavec Janez, Müller Jens
Institute of Inorganic and Analytical Chemistry, Universität Münster, Corrensstr. 30, 48149, Münster, Germany.
Slovenian NMR Centre, National Institute of Chemistry, SI-1000, Ljubljana, Slovenia.
J Biol Inorg Chem. 2025 Aug;30(4-5):381-395. doi: 10.1007/s00775-025-02115-y. Epub 2025 May 2.
The interaction of metal ions with nucleic acids was studied by determining the initial binding sites of Ag ions at unmodified B-DNA by NMR spectroscopy. In particular, NMR spectra were recorded of the Dickerson-Drew dodecamer sequence in the presence of different ratios of Ag ions to DNA. The data indicate that the coordination of the first three Ag ions per duplex preferentially takes place inside the B-DNA helix rather than at other possible binding sites such as the negatively charged phosphate backbone and/or the endocyclic N7 position of purine residues. Larger DNA aggregates are formed in the presence of excess Ag ions, as indicated by the formation of a precipitate and by significant changes in the circular dichroism spectra. As shown by a titration with chloride ions, the Ag ions are only loosely bound to the nucleic acids and can be released by precipitation of AgCl.
通过核磁共振光谱法确定银离子在未修饰的B-DNA上的初始结合位点，研究了金属离子与核酸的相互作用。具体而言，记录了在不同银离子与DNA比例存在下Dickerson-Drew十二聚体序列的核磁共振光谱。数据表明，每个双链体的前三个银离子的配位优先发生在B-DNA螺旋内部，而不是在其他可能的结合位点，如带负电荷的磷酸主链和/或嘌呤残基的内环N7位置。如沉淀的形成和圆二色光谱的显著变化所示，在过量银离子存在下会形成更大的DNA聚集体。如用氯离子滴定所示，银离子仅松散地结合在核酸上，并且可以通过AgCl沉淀而释放。
