Deng Fengyu, Dong Chengyu, Liu Ying
College of Life and Environmental Science, Minzu University of China, Beijing 100081, People's Republic of China.
Mol Biosyst. 2012 Apr;8(5):1446-51. doi: 10.1039/c2mb05467a. Epub 2012 Feb 15.
The interaction of nitrofurazone (NF) and human serum albumin (HSA) has been studied by fluorescence spectroscopy, FT-IR spectroscopy and molecular modeling methods. The results showed that the fluorescence of HSA was quenched by NF in a static quenching mechanism. Thermodynamic parameters revealed that hydrogen bonds and van der Waals force played the major role during the interaction. The calculated binding distance (r) indicated that the non-radioactive energy transfer came into being in the interaction between NF and HSA. HSA had a single class of binding site at Sudlow' site I in subdomain IIA for NF, which was verified by the displacement experiment. The molecular modeling study further confirmed the specific binding sites of NF on HSA, such as the interaction between N11 and N14 of NF with Lue 283 and Ser 287 predominately through hydrogen bonds. Three-dimensional fluorescence spectra indicated that the polarity around the tryptophan residues decreased and the conformation of HSA changed after adding NF. FT-IR spectra showed that NF could induce the polypeptides of HSA unfolding because it changed α-helix and β-sheet into β-turn and random structure of HSA.
通过荧光光谱法、傅里叶变换红外光谱法和分子模拟方法研究了呋喃西林（NF）与人血清白蛋白（HSA）的相互作用。结果表明，NF通过静态猝灭机制猝灭了HSA的荧光。热力学参数表明，氢键和范德华力在相互作用过程中起主要作用。计算得到的结合距离（r）表明，NF与HSA相互作用过程中发生了非辐射能量转移。通过竞争置换实验证实，HSA在IIA亚结构域的Sudlow位点I上有一类单一的NF结合位点。分子模拟研究进一步证实了NF在HSA上的特异性结合位点，例如NF的N11和N14与Leu 283和Ser 287主要通过氢键相互作用。三维荧光光谱表明，加入NF后，色氨酸残基周围的极性降低，HSA的构象发生改变。傅里叶变换红外光谱表明，NF可诱导HSA的多肽展开，因为它将HSA的α-螺旋和β-折叠转变为β-转角和无规结构。
