基于硫碱基(thio-base)的易烷基化、易氧化、强紫外长波(UVA)吸收等独特的性质, 以及核苷类化合物的抗肿瘤活性, 设计合成了一种新化合物4-硫-5-碘尿苷, 通过NMR、 IR、 UV、 MS对其结构进行了表征。在模拟生理条件下, 利用荧光光谱法、紫外-可见吸收光谱法以及圆二色谱法研究了4-硫-5-碘尿苷与人血清白蛋白(HSA)的相互作用。结果表明, 4-硫-5-碘尿苷对HSA荧光具有静态猝灭作用。运用Stern-Volmer方程计算了体系的猝灭常数, 利用Lineweaver-Burk方程计算了二者的结合常数, 并且确定了4-硫-5-碘尿苷与HSA之间的主要作用力类型为疏水作用力, 根据能量转移理论求得4-硫-5-碘尿苷与HSA的结合距离及能量转移率。此外, 通过圆二色谱法考察了4-硫-5-碘尿苷对HSA作用前后的构型结构的影响。

Based on the special properties of thio-base, such as easy to oxidization, alkylation, and the strong absorption of longer ultraviolet wave-UVA, etc., and the anti-tumor activity of nucleoside compounds, a new compound of 4-thio-5-iodouridine was designed and synthesized. The structure was characterized by Infrared spectroscopy, nuclear magnetic resonanceand mass spectrometry. At the same time, the interactions between 4-thio-5-iodouridine and human serum albumin (HSA) were investigated by the fluorescence spectroscopy, ultraviolet-visible absorption spectrum(UV-Vis) and circular dichroism spectrum(CD). The results show that 4-thio-5-iodouridine has a static fluorescence quenching on human serum albumin (HSA). The quenching constants were calculated according to Stern-Volmer equation, and Lineweaver-Burk equation was used to calculate the binding constants. The main forces of both interactions have typical hydrophobic interaction from thermodynamic data to determination. The distance and FRET(fluorescence resonance energy transfer) efficiency between HSA and 4-thio-5-iodouridine were calculated according to Frster resonance energy transfer theory. The conformation of 4-thio-5-iodouridine on human serum albumin was studied using CD.