Institute of Physical Chemistry, Zhejiang Normal University , Jinhua 321004, Zhejiang, China.
School of Chemistry and Molecular Engineering, East China Normal University , Shanghai 200241, China.
Anal Chem. 2017 Feb 21;89(4):2181-2185. doi: 10.1021/acs.analchem.6b04709. Epub 2017 Jan 30.
The rapid identification of biomacromolecule structure that has a specific association with chiral enantiomers especially from natural sources will be helpful in developing enantioselective sensor and in speeding up drug exploitation. Herein, owing to its existence also in living cells, apurinic/apyrimidinic site (AP site) was first engineered into ds-DNA duplex to explore its competence in enantiomer selectivity. An AP site-specific fluorophore was utilized as an enantioselective discrimination probe to develop a straightforward chiral sensor using natural tetrahydropalmatine (L- and D-THP) as enantiomer representatives. We found that only L-THP can efficiently replace the prebound fluorophore to cause a significant fluorescence increase due to its specific binding with the AP site (two orders magnitude higher in affinity than binding with D-THP). The AP site binding specificity of L-THP over D-THP was assessed via intrinsic fluorescence, isothermal titration calorimetry, and DNA stability. The enantioselective performance can be easily tuned by the sequences near the AP site and the number of AP sites. A single AP site provides a perfect binding pocket to differentiate the chiral atom-induced structure discrepancy. We expect that our work will inspire interest in engineering local structures into a ds-DNA duplex for developing novel enantioselective sensors.
快速识别与手性对映体（尤其是天然来源）具有特定关联的生物大分子结构，将有助于开发对映选择性传感器并加速药物开发。在此，由于其也存在于活细胞中，因此首次将无嘌呤/无嘧啶位点（AP 位点）工程化到 ds-DNA 双螺旋中，以探索其在手性选择性方面的能力。AP 位点特异性荧光团被用作对映体选择性识别探针，使用天然延胡索乙素（L-和 D-THP）作为对映体代表物开发了一种简单的手性传感器。我们发现，只有 L-THP 可以有效地取代预结合的荧光团，由于其与 AP 位点的特异性结合，导致荧光显著增加（亲和力比与 D-THP 结合高两个数量级）。通过本征荧光、等温滴定量热法和 DNA 稳定性评估了 L-THP 对 D-THP 的 AP 位点结合特异性。通过 AP 位点附近的序列和 AP 位点的数量可以轻松调整对映选择性性能。单个 AP 位点提供了一个完美的结合口袋，可区分手性原子诱导的结构差异。我们期望我们的工作将激发对手性传感器的研究兴趣，即将局部结构工程化到 ds-DNA 双螺旋中以开发新型对映选择性传感器。
