Sensing metal ions with DNA building blocks: Fluorescent pyridobenzimidazole nucleosides
Sensing metal ions with DNA building blocks: Fluorescent pyridobenzimidazole nucleosides
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DOI：
10.1021/ja0581806
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发表时间：
2006-05-10
影响因子：
15
通讯作者：
Kool, Eric T.
中科院分区：
文献类型：
--
作者：
Kim, Su Jeong;Kool, Eric T.
我们描述了以2-吡啶-2-苯并咪唑和2-奎诺-2-苯并咪唑为苷元的新型N-脱氧核苷(1和2)。这些化合物是由以前未知的杂环前体和霍弗的氯糖制备的，产生的主要产品是α-异构体。X-射线晶体结构证实了这一几何构型，并表明吡啶和苯并咪唑环体系在固相中偏离共面性的程度分别为154和140。在甲醇中，化合物1和2的最大吸收波长分别位于360和370 nm，发射最大波长分别位于494和539 nm。实验揭示了核苷对17种一价、二价和三价金属离子在甲醇中的不同荧光响应。其中一个或两个核苷与10个金属离子发生了显著变化。配体-核苷1最显著的光谱变化包括荧光红移(Au+，Au3+)，强烈猝灭(Cu2+，Ni2+，Pt2+)，以及伴随红移(Ag+，Cd2+，Zn2+)的发射强度显著增强。配体-核苷2的最大光谱变化包括荧光红移(Ag+)、蓝移(Cd~(2+))、强猝灭(Pd~(2+)、Pt~(2+))以及发射强度的显著增强和蓝移(锌~(2+))。这些化合物可以很容易地结合到寡聚脱氧核苷酸中，初步研究表明，它们对水溶液中的金属离子保持着敏感性，并显示了与几个离子可能的协同传感行为。这两个游离的核苷本身就可以作为多种金属离子的差示传感器，它们是潜在的有用的单体，可以为DNA提供金属离子传感能力。
We describe novel fluorescent N-deoxyribosides (1 and 2) having 2-pyrido-2-benzimidazole and 2-quino-2- benzimidazole as aglycones. The compounds were prepared from the previously unknown heterocyclic precursors and Hoffer's chlorosugar, yielding alpha anomers as the chief products. X-ray crystal structures confirmed the geometry and showed that the pyridine and benzimidazole ring systems deviated from coplanarity in the solid state by 154 and 140, respectively. In methanol compounds 1 and 2 had absorption maxima at 360 and 370 nm, respectively, and emission maxima at 494 and 539 nm. Experiments revealed varied fluorescence responses of the nucleosides to a panel of 17 monovalent, divalent, and trivalent metal ions in methanol. One or both of the nucleosides showed significant changes with 10 of the metal ions. The most pronounced spectral changes for ligand-nucleoside 1 included red shifts in fluorescence (Au+, Au3+), strong quenching (Cu2+, Ni2+, Pt2+), and substantial enhancements in emission intensity coupled with red shifts (Ag+, Cd2+, Zn2+). The greatest spectral changes for ligand-nucleoside 2 included a red shift in fluorescence (Ag+), a blue shift (Cd2+), strong quenching (Pd2+, Pt2+), and substantial enhancements in emission intensity coupled with a blue shift (Zn2+). The compounds could be readily incorporated into oligodeoxynucleotides, where an initial study revealed that they retained sensitivity to metal ions in aqueous solution and demonstrated possible cooperative sensing behavior with several ions. The two free nucleosides alone can act as differential sensors for multiple metal ions, and they are potentially useful monomers for contributing metal ion sensing capability to DNAs.