School of Chemistry and Environmental Science, Henan Normal University, Xinxiang, Henan 453007, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2011 Nov;82(1):299-305. doi: 10.1016/j.saa.2011.07.052. Epub 2011 Jul 23.
A benzimidazole derivative, 1-(2-picolyl)-3-(2-picolyl) benzimidazole iodide (PPB), was synthesized. Fourier transform infrared spectroscopy (FT-IR), UV-visible, three-dimensional (3D) fluorescence, synchronous fluorescence (SF) and fluorescence spectroscopic methods were used to determine the PPB binding mode and the effects of PPB on protein stability and secondary structure. Fluorescence results revealed the presence of static type of quenching mechanism in the binding of PPB to human serum albumin (HSA). The binding constants between PPB and HSA were obtained according to Scatchard equation. The number of binding sites, the binding constants and the thermodynamic parameters were measured. The results showed a spontaneous binding of PPB to HSA through hydrogen bonds and van der Waals forces. In addition, the distance between PPB and the Trp 214 was estimated via employing the Förster's non-radiative energy transfer theory, and was found to be 3.49 nm, which indicated that PPB can bind to HSA with high probability. Site marker competitive experiments indicated that the binding of PPB to HSA primarily took place in subdomain IIA.
合成了苯并咪唑衍生物 1-(2-吡啶基)-3-(2-吡啶基)苯并咪唑碘化物（PPB）。采用傅里叶变换红外光谱（FT-IR）、紫外-可见、三维（3D）荧光、同步荧光（SF）和荧光光谱法测定了 PPB 的结合模式以及 PPB 对蛋白质稳定性和二级结构的影响。荧光结果表明，PPB 与人血清白蛋白（HSA）结合存在静态猝灭机制。根据 Scatchard 方程得到了 PPB 与 HSA 的结合常数。测量了结合位点数、结合常数和热力学参数。结果表明，PPB 通过氢键和范德华力自发结合到 HSA 上。此外，通过采用福斯特非辐射能量转移理论估算了 PPB 与色氨酸 214 之间的距离，发现为 3.49nm，表明 PPB 极有可能与 HSA 结合。位点标记竞争实验表明，PPB 与 HSA 的结合主要发生在亚域 IIA。
