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目的研究牛血清白蛋白在脲中的构象变化过程,根据荧光参数的变化,建立蛋白构象与环境变化的关系,从分子水平探讨蛋白质构象变化而致不稳定的原因。方法采用内源性荧光法、荧光淬灭法及荧光探针法研究牛血清白蛋白在脲中的构象变化过程。结果随着脲浓度的增加,牛血清白蛋白中内源性色氨酸荧光峰位先蓝移后红移,荧光强度逐步衰减;而8-苯胺基-1-萘磺酸与牛血清白蛋白结合物的荧光峰位则逐步红移,荧光强度逐渐衰减。结论在变性过程中,牛血清白蛋白的色氨酸残基所处区域构象经历了一个先紧缩后舒展的三态过程;而8-苯胺基-1-萘磺酸的探针结合位点与色氨酸残基可能位于牛血清白蛋白的不同区域,且构象变化更为灵敏。
Objective To study the conformational change of bovine serum albumin (BSA) in urea. The relationship between protein conformation and environmental changes was established based on the changes of fluorescence parameters. The molecular instability of the protein conformation was explored. Methods The conformational changes of bovine serum albumin (BSA) in urea were studied by endogenous fluorescence, fluorescence quenching and fluorescence probe methods. Results With the increase of urea concentration, the peak of endogenous tryptophan fluorescence in bovine serum albumin shifted to red-shifted after blue-shift and the fluorescence intensity decreased gradually. However, the concentration of 8-anilino-1-naphthalenesulfonic acid and bovine serum albumin The fluorescent peak of the conjugate gradually red-shifted, and the fluorescence intensity gradually decayed. Conclusions During the denaturation, the conformation of tryptophan residues in bovine serum albumin undergoes a three-state process of shrinking and stretching first. However, the binding sites of 8-anilino-1-naphthalene sulfonic acid Tryptophan residues may be located in different regions of bovine serum albumin, and conformational changes more sensitive.