【摘要】 采用紫外-可见吸收光谱和荧光光谱方法研究了菌紫质(Bacteriorhodopsin,bR)中的8个色氨酸(Tryptophan,Trp)残基在被N-溴代琥珀酰亚胺(N-bromosuccinimide,NBS)修饰过程中的残基数目及对应的光谱变化。研究结果显示:随着NBS/bR摩尔比例增加逐渐被修饰的Trp残基有4个左右,如果NBS过量,则Trp残基的修饰个数最终可达6～7个;伴随化学修饰出现Trp残基特征荧光峰值下降及峰位蓝移。研究结果揭示了bR中Trp残基可能的三种结构分布,对于进一步弄清bR中Trp-视黄醛(Retinal)偶联能量传递、单独Trp残基的荧光寿命和Trp残基在膜蛋白结构和功能中的作用具有积极而重要的意义。更多还原

【Abstract】 The number of oxidized Tryptophan(Trp)of all the eight Trp residues of bR and the corresponding spectrum change when modified by N-bromosuccinimide(NBS)gradually(redox)via UV-Vis absorption spectrum and fluorescence spectrum were researched.The results revealed that the number of oxidized Trp residues is about 4 when increasing the NBS/bR molar ratio normally,but if more NBS is used,This number will rise to 6~7.The Trp residues’ characteristic fluorescence peak will be decreased and blue-shifted during the chemical modification.Results revealed still that there may be three different kinds of Trp residue structure in bR.The research results are important and meaningful for making clear the Trp-retinal coupling energy transfer,the fluorescence lifetime of individual Trp residue and the role of Trp residues in membrane protein’s structure and function.更多还原