School of Science, TianJin ChengJian University, Tianjin, China; Tianjian Engineering Technology Center of Chemical Waste-water Source Reduction and Recycling, Tianjin, China.
School of Science, TianJin ChengJian University, Tianjin, China.
J Mol Graph Model. 2021 May;104:107842. doi: 10.1016/j.jmgm.2021.107842. Epub 2021 Jan 11.
To study the binding mechanism of 4',6-diamidino-2-phenylindole (DAPI) and polyphosphate (Poly-P) and find fluorescent dyes which can dye Poly-P better, the interaction model of DAPI and Poly-P was calculated by the self-consistent-charge, density functional tight-binding (SCC-DFTB-D) method, and the binding sites of DAPI and Poly-P were analyzed. Further, Cy3, Rhodamine 6G and Fluorescein, which are structurally similar to DAPI, were selected to analyze their interactions with Poly-P. The binding energies and frontier orbital properties of the complexes were analyzed. These four fluorescent dyes were further used to dye the activated sludge smear and observe the fluorescence property. The Simulation results show that the N-containing indole ring structures in DAPI plays an important role in the interaction with Poly-P; the binding energies for DAPI, Cy3, Rhodamine 6G and Fluorescein with Poly-P are -42.6, -165.4, -34.7 and -28.9 kcal/mol, respectively. The frontier orbital properties for the complexes were studied, which further indicates that the interactions between Cy3, Rhodamine 6G and Poly-P are stronger than that of Fluorescein and Poly-P. The experimental results showed that Cy3 had excellent dyeing effect on Poly-P and could recognize them, while Fluorescein could not dye Poly-P. The experimental results were in good agreement with those predicted by simulation, which verified the correctness of our calculation method and provided a new strategy for finding more reliable, more sensitive and more economical fluorescent dyes capable of dyeing Poly-P.
为了研究 4',6-二脒基-2-苯基吲哚（DAPI）与多聚磷酸盐（Poly-P）的结合机制，寻找能更好地染 Poly-P 的荧光染料，采用自洽 charge、密度泛函紧束缚（SCC-DFTB-D）方法计算了 DAPI 与 Poly-P 的相互作用模型，并对 DAPI 与 Poly-P 的结合位点进行了分析。进一步选择与 DAPI 结构相似的 Cy3、Rhodamine 6G 和荧光素，分析它们与 Poly-P 的相互作用。分析了复合物的结合能和前线轨道性质。进一步用这四种荧光染料对活性污泥涂片进行染色，观察其荧光性质。模拟结果表明，DAPI 中含 N 的吲哚环结构在与 Poly-P 的相互作用中起重要作用；DAPI、Cy3、Rhodamine 6G 和 Fluorescein 与 Poly-P 的结合能分别为-42.6、-165.4、-34.7 和-28.9 kcal/mol。对复合物的前线轨道性质进行了研究，进一步表明 Cy3、Rhodamine 6G 与 Poly-P 的相互作用强于 Fluorescein 与 Poly-P 的相互作用。实验结果表明 Cy3 对 Poly-P 具有良好的染色效果，能够识别 Poly-P，而 Fluorescein 则不能对 Poly-P 进行染色。实验结果与模拟预测结果吻合较好，验证了我们计算方法的正确性，为寻找更可靠、更灵敏、更经济的染 Poly-P 的荧光染料提供了新策略。
