School of Chemistry and Chemical Engineering, Nantong University, Nantong 226019, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2011 Oct 15;81(1):645-52. doi: 10.1016/j.saa.2011.06.068. Epub 2011 Jul 2.
The studies on the interaction between HSA and drugs have been an interesting research field in life science, chemistry and clinical medicine. There are also many metal ions present in blood plasma, thus the research about the effect of metal ions on the interaction between drugs and plasma proteins is crucial. In this study, the interaction of Salvianolic acid B (Sal B) with human serum albumin (HSA) was investigated by the steady-state, synchronous fluorescence and circular dichroism (CD) spectroscopies. The results showed that Sal B had a strong ability to quench the intrinsic fluorescence of HSA through a static quenching mechanism. Binding parameters calculated showed that Sal B was bound to HSA with the binding affinities of 10(5) L mol(-1). The thermodynamic parameters studies revealed that the binding was characterized by positive enthalpy and positive entropy changes, and hydrophobic interactions were the predominant intermolecular forces to stabilize the complex. The specific binding distance r (2.93 nm) between donor (HSA) and acceptor (Sal B) was obtained according to Förster non-radiative resonance energy transfer theory. The synchronous fluorescence experiment revealed that Sal B cannot lead to the microenvironmental changes around the Tyr and Trp residues of HSA, and the binding site of Sal B on HSA is located in hydrophobic cavity of subdomain IIA. The CD spectroscopy indicated the secondary structure of HSA is not changed in the presence of Sal B. Furthermore, The effect of metal ions (e.g. Zn(2+), Cu(2+), Co(2+), Ni(2+), Fe(3+)) on the binding constant of Sal B-HSA complex was also discussed.
人血清白蛋白与药物的相互作用研究一直是生命科学、化学和临床医学中一个有趣的研究领域。血浆中也存在许多金属离子，因此研究金属离子对药物与血浆蛋白相互作用的影响至关重要。本研究采用稳态、同步荧光和圆二色（CD）光谱法研究了丹酚酸 B（Sal B）与人血清白蛋白（HSA）的相互作用。结果表明，Sal B 通过静态猝灭机制强烈地猝灭了 HSA 的内源性荧光。计算得到的结合参数表明，Sal B 与 HSA 结合的亲和力为 10(5) L/mol。热力学参数研究表明，结合过程的主要驱动力是疏水相互作用，其特征是焓变和熵变均为正值。根据福斯特非辐射共振能量转移理论，计算得到供体（HSA）和受体（Sal B）之间的特定结合距离 r（2.93nm）。同步荧光实验表明，Sal B 不会导致 HSA 中 Tyr 和 Trp 残基周围微环境的变化，Sal B 在 HSA 上的结合位点位于 IIA 亚结构域的疏水腔中。CD 光谱表明，Sal B 的存在并未改变 HSA 的二级结构。此外，还讨论了金属离子（如 Zn(2+)、Cu(2+)、Co(2+)、Ni(2+)、Fe(3+)）对 Sal B-HSA 配合物结合常数的影响。
