Photosciences and Photonics, Chemical Sciences and Technology Division, National Institute for Interdisciplinary Science and Technology (NIIST), CSIR, Trivandrum, 695019, India.
Org Biomol Chem. 2011 Feb 21;9(4):1021-9. doi: 10.1039/c0ob00673d. Epub 2011 Jan 5.
We synthesized a few novel cyclophanes CP-1 to CP-4 containing anthracene units linked together through different bridging and spacer groups and have investigated their interactions with various nucleosides and nucleotides. Of these systems, CP-1 and CP-3 showed selectivity for 5'-GTP and 5'-ATP as compared to other nucleotides and nucleosides, whereas negligible selectivity was observed with CP-2 and CP-4. Interestingly, CP-1, CP-2 and CP-3 exhibited significant binding interactions with the fluorescent indicator, 8-hydroxy-1,3,6-pyrene trisulfonate (HPTS), resulting in the formation of non-fluorescent complexes. Titration of these complexes with nucleosides and nucleotides resulted in the displacement of HPTS, leading to the revival of its fluorescence intensity. It was observed that 5'-GTP induced the maximum displacement of HPTS from the complex [CP-1·HPTS] with an overall fluorescence enhancement of ca. 150-fold, while 5'-ATP induced ca. 45-fold. Although the displacement of HPTS from the complexes [CP-2·HPTS] and [CP-3·HPTS] was found to be similar to that of [CP-1·HPTS], these complexes showed lesser selectivity and sensitivity. In contrast, negligible displacement of HPTS was observed from the complex [CP-4·HPTS] under similar conditions. These results indicate that CP-1, having a well-defined cavity and good electron acceptor (viologen), is capable of forming selective and stable complexes. Though CP-2 and CP-3 retain the good electron acceptor (viologen), their reduced aromatic surface and larger cavity, respectively, resulted in lesser sensitivity. In contrast, CP-4 having a large cavity and a poor acceptor (1,2-bis(pyridin-4-yl)ethene) showed negligible selectivity, thereby indicating the importance of cavity size, bridging unit and aromatic surface on biomolecular recognition properties of cyclophanes.
我们合成了几个含有蒽单元的新型环芳烃 CP-1 到 CP-4，这些单元通过不同的桥连和间隔基团连接在一起，并研究了它们与各种核苷和核苷酸的相互作用。在这些体系中，CP-1 和 CP-3 对 5'-GTP 和 5'-ATP 表现出选择性，而对其他核苷酸和核苷则几乎没有选择性，而 CP-2 和 CP-4 则没有表现出选择性。有趣的是，CP-1、CP-2 和 CP-3 与荧光指示剂 8-羟基-1,3,6-三磺酸基芘（HPTS）表现出显著的结合相互作用，导致形成非荧光复合物。用核苷和核苷酸滴定这些复合物导致 HPTS 的置换，从而恢复其荧光强度。观察到 5'-GTP 诱导 HPTS 从复合物 [CP-1·HPTS] 中最大程度的置换，总荧光增强约 150 倍，而 5'-ATP 诱导约 45 倍。尽管从复合物 [CP-2·HPTS] 和 [CP-3·HPTS] 中置换 HPTS 的情况与从 [CP-1·HPTS] 中置换 HPTS 的情况相似，但这些复合物的选择性和灵敏度较低。相比之下，在类似条件下，从复合物 [CP-4·HPTS] 中几乎没有观察到 HPTS 的置换。这些结果表明，CP-1 具有明确的空腔和良好的电子受体（紫精），能够形成选择性和稳定的复合物。虽然 CP-2 和 CP-3 保留了良好的电子受体（紫精），但它们分别具有较小的芳香表面和较大的空腔，导致灵敏度降低。相比之下，CP-4 具有较大的空腔和较差的受体（1,2-双（吡啶-4-基）乙烯），表现出几乎没有选择性，从而表明空腔大小、桥连单元和芳香表面对环芳烃生物分子识别性质的重要性。
