State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Si Pai Lou 2#, Nanjing 210096, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2009 Dec;74(5):1224-8. doi: 10.1016/j.saa.2009.09.040. Epub 2009 Oct 4.
The interaction of 6-thioguanine (6-TG) and bovine serum albumin (BSA) in the absence and presence of denaturant (urea and Guanidine hydrochloride) was investigated by fluorescence spectroscopic techniques. Changes of fluorescence intensity both in F(304) and in F(348) of BSA reflected increasing participation of tyrosine fluorescence in the total emission with increasing denaturant, which indicated that energy transfer from tyrosyl residues to tryptophanyl residues became less efficient in the denatured tertiary protein structure. The quenching effects of 6-TG were shown not only on the native but also on the unfolded form of BSA. The quenching constants and binding constants were calculated from the fluorescence spectra of the BSA/6-TG complex both in the absence and presence of the denaturant. The data suggested that the quenching constants and binding constants of 6-TG for BSA decreased with increasing concentration of denaturant. The spectroscopic analysis also showed antidenaturant properties of 6-TG under both denaturant conditions.
用荧光光谱技术研究了 6-硫代鸟嘌呤（6-TG）与牛血清白蛋白（BSA）在非变性和变性（尿素和盐酸胍）条件下的相互作用。BSA 的 F(304)和 F(348)荧光强度的变化反映了随着变性剂浓度的增加，酪氨酸荧光在总发射中的参与程度增加，这表明在变性的三级蛋白质结构中，色氨酸残基向酪氨酸残基的能量转移效率降低。6-TG 的猝灭效应不仅发生在 BSA 的天然形式上，也发生在展开形式上。从 BSA/6-TG 复合物在非变性和变性条件下的荧光光谱计算了猝灭常数和结合常数。数据表明，随着变性剂浓度的增加，6-TG 对 BSA 的猝灭常数和结合常数降低。光谱分析还表明，在两种变性条件下，6-TG 均具有抗变性剂的性质。
