Kim Su Jeong, Kool Eric T
Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA.
J Am Chem Soc. 2006 May 10;128(18):6164-71. doi: 10.1021/ja0581806.
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 degrees and 140 degrees , 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(+), Au(3+)), strong quenching (Cu(2+), Ni(2+), Pt(2+)), and substantial enhancements in emission intensity coupled with red shifts (Ag(+), Cd(2+), Zn(2+)). The greatest spectral changes for ligand-nucleoside 2 included a red shift in fluorescence (Ag(+)), a blue shift (Cd(2+)), strong quenching (Pd(2+), Pt(2+)), and substantial enhancements in emission intensity coupled with a blue shift (Zn(2+)). 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.
我们描述了以2-吡啶-2-苯并咪唑和2-喹啉-2-苯并咪唑为糖苷配基的新型荧光N-脱氧核糖苷（1和2）。这些化合物由先前未知的杂环前体和霍费尔氯糖制备而成，主要产物为α异头物。X射线晶体结构证实了其几何形状，并表明吡啶和苯并咪唑环系统在固态下分别偏离共面154度和140度。在甲醇中，化合物1和2的吸收最大值分别为360和370nm，发射最大值分别为494和539nm。实验揭示了这些核苷在甲醇中对一组17种单价、二价和三价金属离子的荧光响应各不相同。其中一种或两种核苷对10种金属离子表现出显著变化。配体 - 核苷1最显著的光谱变化包括荧光红移（Au(+)、Au(3+)）、强烈猝灭（Cu(2+)、Ni(2+)、Pt(2+)）以及发射强度大幅增强并伴有红移（Ag(+)、Cd(2+)、Zn(2+)）。配体 - 核苷2最大的光谱变化包括荧光红移（Ag(+)）、蓝移（Cd(2+)）、强烈猝灭（Pd(2+)、Pt(2+)）以及发射强度大幅增强并伴有蓝移（Zn(2+)）。这些化合物可以很容易地掺入寡脱氧核苷酸中，初步研究表明它们在水溶液中仍保留对金属离子的敏感性，并展示了与几种离子可能的协同传感行为。仅这两种游离核苷就可以作为多种金属离子的差分传感器，并且它们是潜在有用的单体，可为DNA赋予金属离子传感能力。
