Kong Deyong, Qin Cui, Fan Ping, Li Bing, Wang Jun
College of Chemistry, Liaoning University, Shenyang 110036, PR China.
College of Chemistry, Liaoning University, Shenyang 110036, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2015 Apr 5;140:372-81. doi: 10.1016/j.saa.2015.01.004. Epub 2015 Jan 13.
An novel aromatic aminopolycarboxylic acid ligand, N-(2-N,N-Dicarboxymethylaminophenyl) ethylenediamine-N,N',N'-triacetic acid (H5ph-dtpa), was synthesized by improving experimental method and its corresponding Eu(III) complex, Na2[EuIII(ph-dtpa)(H2O)]·6H2O, was successfully prepared through heat-refluxing method. As a comparison, the Eu(III) complex with diethylenetriamine-N,N,N',N',N″-pentaacetic acid (H5dtpa) ligand, Na2[Eu(III)(dtpa)(H2O)]·6H2O, was also prepared by the same method. And then, the interaction between prepared Eu(III) complexes ([EuIII(dtpa)(H2O)]2- and [EuIII(ph-dtpa)(H2O)]2-) and bovine serum albumin (BSA) in aqueous solution were studied by the combination of ultraviolet-visible (UV-vis), fluorescence and circular dichroism (CD) spectroscopies. In addition, the binding sites of Eu(III) complexes ([EuIII(dtpa)(H2O)]2- and [EuIII(ph-dtpa)(H2O)]2-) to BSA molecules were also estimated by synchronous fluorescence. Moreover, the theoretical and experimental results show that the Van der Waals, hydrogen bond and π-π stacking interactions are the mainly impulse to the reaction. The binding distances (r) between Eu(III) complexes ([EuIII(dtpa)(H2O)]2- and [EuIII(ph-dtpa)(H2O)]2-) and BSA were obtained according to Förster's non-radiative energy transfer theory. Also, the determined UV-vis absorption spectroscopy, synchronous fluorescence and circular dichroism (CD) spectra showed that the conformation of BSA could be changed in the presence of Eu(III) complexes. The obtained results can help understand the action mode between rare earth metal complexes of aminopolycarboxylic acid ligands with BSA and they are also expected to provide important information of designs of new inspired drugs.
通过改进实验方法合成了一种新型芳香族氨基多羧酸配体N-(2-N,N-二羧甲基氨基苯基)乙二胺-N,N',N'-三乙酸(H5ph-dtpa)，并采用热回流法成功制备了其相应的铕(III)配合物Na2[EuIII(ph-dtpa)(H2O)]·6H2O。作为对比，同样采用该方法制备了含有二乙烯三胺-N,N,N',N',N″-五乙酸(H5dtpa)配体的铕(III)配合物Na2[Eu(III)(dtpa)(H2O)]·6H2O。然后，通过紫外可见(UV-vis)光谱、荧光光谱和圆二色(CD)光谱联用，研究了所制备的铕(III)配合物([EuIII(dtpa)(H2O)]2-和[EuIII(ph-dtpa)(H2O)]2-)与牛血清白蛋白(BSA)在水溶液中的相互作用。此外，还通过同步荧光法估算了铕(III)配合物([EuIII(dtpa)(H2O)]2-和[EuIII(ph-dtpa)(H2O)]2-)与BSA分子的结合位点。而且，理论和实验结果表明，范德华力、氢键和π-π堆积相互作用是该反应的主要驱动力。根据Förster非辐射能量转移理论，得到了铕(III)配合物([EuIII(dtpa)(H2O)]2-和[EuIII(ph-dtpa)(H2O)]2-)与BSA之间的结合距离(r)。同时，所测定的紫外可见吸收光谱、同步荧光光谱和圆二色(CD)光谱表明，在铕(III)配合物存在的情况下，BSA的构象可能会发生变化。所得结果有助于理解氨基多羧酸配体的稀土金属配合物与BSA之间的作用模式，也有望为新型启发式药物的设计提供重要信息。
