State Key Laboratory of Virology and Department of Chemistry, Wuhan University, Wuhan 430072, People's Republic of China.
Biomacromolecules. 2010 Jan 11;11(1):106-12. doi: 10.1021/bm900961e.
In this study, fluorescence spectroscopy in combination with UV-vis absorption spectroscopy and circular dichroism (CD) spectroscopy was employed to investigate the high affinity binding of palmatine to human serum albumin (HSA) under the physiological conditions. In the mechanism discussion it was proved that the fluorescence quenching of HSA by palmatine is a result of the formation of palmatine/HSA complex. Binding parameters calculating from Stern-Volmer method and Scatchard method showed that palmatine bind to HSA with the binding affinities of the order 10(4) L.mol(-1). The thermodynamic parameters studies revealed that the binding was characterized by negative enthalpy and positive entropy changes and the electrostatic interactions play a major role for palmatine-HSA association. Site marker competitive displacement experiments demonstrating that palmatine bind with high affinity to site I (subdomain IIA) of HSA. The specific binding distance r (2.91 nm) between donor (Trp-214) and acceptor (palmatine) was obtained according to fluorescence resonance energy transfer (FRET). Furthermore, the CD spectral result indicates that the secondary structure of HSA was changed in the presence of palmatine.
在这项研究中，荧光光谱学结合紫外-可见吸收光谱学和圆二色性（CD）光谱学被用来研究在生理条件下黄连碱与人血清白蛋白（HSA）的高亲和力结合。在机制讨论中，证明了黄连碱对 HSA 的荧光猝灭是形成黄连碱/HSA 复合物的结果。从 Stern-Volmer 方法和 Scatchard 方法计算的结合参数表明，黄连碱与 HSA 结合的亲和力顺序为 10(4) L.mol(-1)。热力学参数研究表明，结合的特征是负焓和正熵变化，静电相互作用对黄连碱-HSA 结合起主要作用。位点标记竞争置换实验表明，黄连碱与 HSA 的 I 位点（亚域 IIA）具有高亲和力结合。根据荧光共振能量转移（FRET），获得了供体（色氨酸-214）和受体（黄连碱）之间的特定结合距离 r（2.91nm）。此外，CD 光谱结果表明，在存在黄连碱的情况下，HSA 的二级结构发生了变化。
