Barratt M D, Rickwood D M
Biophys Chem. 1984 Jan;19(1):69-73. doi: 10.1016/0301-4622(84)85007-3.
The binding site for 3,3',4',5-tetrachlorosalicylanilide (T4CS), a potent photoallergen, on human serum albumin (HSA) was studied by electron spin resonance spectroscopy using a spin-labelled analogue 3,5-dichlorosalicylamido-4-(2,2,6,6-tetramethylpiperidine 1-oxyl) (DCS-TEMPO) of T4CS in the absence of ultraviolet irradiation. DCS-TEMPO bound non-covalently (K = 5.8 X 10(6) M-1) to one major binding site on HSA. This binding site could be blocked by the photochemical binding of T4CS to the protein. Limited tryptic digestion of HSA or chemical modification of its single tryptophan residue with 2-hydroxy-5-nitrobenzyl bromide was found to reduce the binding constant of the T4CS/DCS-TEMPO-binding site. These observations are in good agreement with earlier conclusions on the nature of the T4CS-binding site and suggest a location for this site close to the single tryptophan residue of the HSA molecule.
利用自旋标记类似物3,5 - 二氯水杨酰胺基 - 4 -（2,2,6,6 - 四甲基哌啶1 - 氧基）（DCS - TEMPO），通过电子自旋共振光谱法在无紫外线照射的情况下研究了强效光变应原3,3',4',5 - 四氯水杨酰苯胺（T4CS）与人血清白蛋白（HSA）的结合位点。DCS - TEMPO以非共价方式（K = 5.8×10⁶ M⁻¹）结合到HSA上的一个主要结合位点。该结合位点可被T4CS与蛋白质的光化学结合所阻断。发现对HSA进行有限的胰蛋白酶消化或用2 - 羟基 - 5 - 硝基苄基溴对其单个色氨酸残基进行化学修饰会降低T4CS / DCS - TEMPO结合位点的结合常数。这些观察结果与关于T4CS结合位点性质的早期结论高度一致，并表明该位点位于靠近HSA分子单个色氨酸残基的位置。
