Hg^(2+)与NBS修饰前后两种血清蛋白结合的研究(英文)  

Study on Binding of Hg^(2+) to Native or NBS Modified BSA and HSA

作　　者：孟乐[1] 袁向华[1] 张年辉[1] 晋军[2] 杜林方[1] 

机构地区：[1]四川大学生命科学学院,成都610064 [2]四川大学分析测试中心,成都610064

出　　处：《四川大学学报（自然科学版）》2006年第1期184-189,共6页Journal of Sichuan University(Natural Science Edition)

摘　　要：外加毫摩尔浓度的重金属离子Hg2+,会引起BSA或HSA的色氨酸荧光下降,并且35℃时的变化比25℃时更明显,HSA的变化比BSA的大.SternVol mer作图分析结果表明荧光淬灭主要是由动态淬灭引起的.用NBS对BSA和HSA的色氨酸残基进行特异性修饰后,Hg2+只引起NBS修饰的HSA的酪氨酸荧光轻微降低,但对NBS修饰的BSA的酪氨酸荧光几乎没有影响.远紫外和近紫外CD谱分析表明:Hg2+的结合要引起BSA,HSA以及NBS修饰的HSA二级结构的α螺旋减少,三级结构发生一定的改变.这些结果表明BSA和HSA中色氨酸附近的二硫桥可能是Hg2+的作用部位.Hg （Ⅱ） induces quenching of trytophan fluorescence of BSA and HSA, and the quenching of HSA is more intense; the change of fluorescence intensity at 35℃ is more dramatic than that at 25℃. Stern Volmer plots indicate the occurrence of dynamic quenching. Hg （Ⅱ） can only induce slight decrease of tyrosine fluorescence of NBS modified HSA, but has no effect on that of modified BSA. Far-UV and near-UV CD spectra provide evidence that the binding of Hg （Ⅱ） induces BSA, HSA and NBS modified HSA a loss of a-helix and rearrangement of tertiary structure. These results suggest that the binding sits of Hg （Ⅱ） is the disulfide bridges in the proximity of the tryptophan residues in BSA and HSA.

关 键 词：HG^2+ 内源荧光 圆二色谱 NBS修饰 血清蛋白 

分 类 号：Q518.4[生物学—生物化学]