Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Fukuoka 819-0395, Japan.
J Am Chem Soc. 2011 Nov 2;133(43):17370-4. doi: 10.1021/ja2057924. Epub 2011 Oct 11.
A novel amphiphilic Tb(3+) complex (TbL(+)) having anionic bis(pyridine) arms and a hydrophobic alkyl chain is developed. It spontaneously self-assembles in water and gives stable vesicles that show sensitized luminescence of Tb(3+) ions at neutral pH. This TbL(+) complex is designed to show coordinative unsaturation, i.e., water molecules occupy some of the first coordination spheres and are replaceable upon binding of phosphate ions. These features render TbL(+) self-assembling receptor molecules which show increase in the luminescence intensity upon binding of nucleotides. Upon addition of adenosine triphosphate (ATP), significant amplification of luminescent intensity was observed. On the other hand, ADP showed moderately increased luminescence and almost no enhancement was observed for AMP. Very interestingly, the increase in luminescence intensity observed for ATP and ADP showed sigmoidal dependence on the concentration of added nucleotides. It indicates positive cooperative binding of these nucleotides to TbL(+) complexes preorganized on the vesicle surface. Self-assembly of amphiphilic Tb(3+) receptor complexes provides nanointerfaces which selectively convert and amplify molecular information of high energy phosphates linked by phosphoanhydride bonds into luminescence intensity changes.
一种具有阴离子双吡啶臂和疏水性烷基链的新型两亲性 Tb(3+) 配合物（TbL(+)）被开发出来。它在水中自发自组装，形成稳定的囊泡，在中性 pH 值下显示 Tb(3+)离子的敏化发光。这种 TbL(+) 配合物被设计为具有配位不饱和性，即水分子占据部分第一配体球，并且可以在结合磷酸根离子时被取代。这些特性使 TbL(+) 自组装受体分子在结合核苷酸时显示出发光强度的增加。加入三磷酸腺苷 (ATP) 后，观察到发光强度的显著放大。另一方面，ADP 显示出中等程度的发光增强，而 AMP 几乎没有增强。非常有趣的是，对于 ATP 和 ADP，观察到的发光强度增加与添加核苷酸的浓度呈 S 形依赖性。这表明这些核苷酸与预先组织在囊泡表面上的 TbL(+) 配合物的正协同结合。两亲性 Tb(3+) 受体配合物的自组装提供了纳米界面，这些界面可以选择性地将通过磷酸酐键连接的高能磷酸化合物的分子信息转化并放大为发光强度变化。
