全硫取代三苯甲基自由基酯基衍生物与牛血清白蛋白的相互作用

采用荧光光谱、电子顺磁共振（EPR）波谱、紫外-可见吸收光谱和分子对接等技术研究了全硫取代三苯甲基（TAM）自由基酯基衍生物ET-03与牛血清白蛋白（BSA）的相互作用，发现ET--03与BSA能自发发生结合作用；主要以疏水作用力结合在BSA亚结构域ⅡA（位点Ⅰ）和亚结构域ⅢA（位点Ⅱ）上；ET-03对BSA的荧光猝灭效应为动态、静态混合猝灭机制，且可能存在非辐射能量转移.研究结果表明，酯基衍生化TAM自由基与白蛋白能自发结合，有望用于蛋白构效关系研究；同时也提示将TAM自由基酯基衍生物用于活体成像或自旋标记物时应考虑其与蛋白相互作用的影响.

Characterization of the Interaction Between Esterified TAM Radical and Bovine Serum Albumin

Fully substituted tetrathiatriarylmethyl(TAM) radicals and their derivatives are ideal electron paramagnetic resonance(EPR) spectroscopy/imaging probe and have been received much concern in NMR contrast agent or spin traps fields.This work demonstrated that an esterified TAM radical(ET-03) bound to bovine serum albumin(BSA) in aqueous solution with fluorescence, electron paramagnetic resonance(EPR) spectroscopy, UV-Vis spectroscopy and molecular docking.The results showed that ET-03 spontaneously bound to BSA.The binding between ET-03 and BSA was driven by a hydrophobic interaction and the binding site was mainly determined to be the sub-domain ⅡA(Sudlow's site Ⅰ) and the sub-domain ⅢA(Sudlow's site Ⅱ).The fluorescence quenching of BSA by ET-03 was a mixture of static and dynamic mechanism with energy transfer probably.This protein binding of the esterified TAM probe to albumin can be used to study the structure and function of albumin and also must be considered for its use as an in vivo imaging agent or spin label.