Grenoble University, CEA, CNRS, INAC-SyMMES, F-38000, Grenoble, France.
CNRS UMR 8516, Lille University, LASIR Institute-Bâtiment C5, Avenue Paul Langevin, F-59655, Villeneuve d'Ascq, France.
Sci Rep. 2019 Aug 29;9(1):12602. doi: 10.1038/s41598-019-48935-2.
Selective binding to nucleic acids and, more generally, to biopolymers, very often requires at a minimum the presence of specific functionalities and precise spatial arrangement. DNA can fold into defined 3D structures upon binding to metal centers and/or lanthanides. Binding efficiency can be boosted by modified nucleosides incorporated into DNA sequences. In this work the high selectivity of modified nucleosides towards copper (II) ions, when used in the monomeric form, is unexpectedly and drastically reduced upon being covalently attached to the DNA sequence in single-site scenario. Surprisingly, such selectivity is partially retained upon non-covalent (i.e. intercalation) mixture formed by native DNA duplex and a nucleoside in the monomeric form. Exploiting the electron spin properties of such different and rich binding mode scenarios, 1D/2D pulsed EPR experiments have been used and tailored to differentiate among the different modes. An unusual correlation of dispersion of hyperfine couplings and strength of the binding mode(s) is described.
选择性地与核酸结合，更广泛地与生物聚合物结合，通常至少需要特定的功能和精确的空间排列。DNA 可以在与金属中心和/或镧系元素结合时折叠成特定的 3D 结构。通过将修饰的核苷掺入 DNA 序列中，可以提高结合效率。在这项工作中，当修饰的核苷以单体形式使用时，对铜（II）离子具有很高的选择性，但当以单一位点方式共价连接到 DNA 序列时，其选择性出乎意料且大大降低。令人惊讶的是，当非共价（即嵌入）混合由天然 DNA 双链体和单体形式的核苷形成时，这种选择性部分保留。利用这种不同且丰富的结合模式场景的电子自旋特性，已经使用了 1D/2D 脉冲 EPR 实验，并对其进行了调整以区分不同的模式。描述了一种超精细耦合分散和结合模式强度之间异常相关的情况。
