Xiao Qi, Huang Shan, Qi Zu-De, Zhou Bo, He Zhi-Ke, Liu Yi
State Key Laboratory of Virology, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, PR China.
Biochim Biophys Acta. 2008 Jul-Aug;1784(7-8):1020-7. doi: 10.1016/j.bbapap.2008.03.018. Epub 2008 Apr 16.
Water-soluble luminescent colloidal quantum dots (QDs) have attracted great attention in biological and medical applications. In particular, for any potential in vivo application, the interaction of QDs with human serum albumin (HSA) is crucial. As a step toward the elucidation of the fate of QDs introduced to organism, the interactions between QDs and HSA were systematically investigated by various spectroscopic techniques under the physiological conditions. It was proved that binding of QDs and HSA is a result of the formation of QDs-HSA complex and electrostatic interactions play a major role in stabilizing the complex. The modified Stern-Volmer quenching constant K(a) at different temperatures and corresponding thermodynamic parameters DeltaH, DeltaG and DeltaS were calculated. Furthermore, the site marker competitive experiments revealed that the binding location of QDs with HSA is around site I, centered at Lys199. The conformational changes of HSA induced by QDs have been analyzed by means of CD and FT-IR. The results suggested that HSA underwent substantial conformational changes at both secondary and tertiary structure levels. The stoichiometry of HSA attached to QDs was obtained by dynamic light scattering (DLS) and zeta-potential.
水溶性发光胶体量子点（QDs）在生物和医学应用中引起了极大关注。特别是对于任何潜在的体内应用，量子点与人血清白蛋白（HSA）的相互作用至关重要。作为阐明引入生物体的量子点命运的一步，在生理条件下通过各种光谱技术系统地研究了量子点与HSA之间的相互作用。结果表明，量子点与HSA的结合是形成量子点-HSA复合物的结果，并且静电相互作用在稳定复合物中起主要作用。计算了不同温度下的修正Stern-Volmer猝灭常数K(a)以及相应的热力学参数ΔH、ΔG和ΔS。此外，位点标记竞争实验表明，量子点与HSA的结合位置在I位点附近，以Lys199为中心。通过圆二色光谱（CD）和傅里叶变换红外光谱（FT-IR）分析了量子点诱导的HSA构象变化。结果表明，HSA在二级和三级结构水平上都发生了显著的构象变化。通过动态光散射（DLS）和zeta电位获得了附着在量子点上的HSA的化学计量比。
