两种化学修饰菌紫质的光化循环和光电位  

THE PHOTOCYCLE AND PHOTOOPTENTIAL OF TWO KINDS OF CHEMICAL MODIFIED BACTERIORHODOPSIN

作　　者：施桦[1] 孙英[1] 张清刚[1] 胡坤生[1] 

机构地区：[1]中国科学院生物物理所,北京100101

出　　处：《生物物理学报》1992年第3期407-411,共5页Acta Biophysica Sinica

摘　　要：本文分别用两种氮氧自由基对菌紫质(bR)中的两种氨基酸残基——赖氨酸和丝氨酸进行了修饰,并对修饰后的bR光循环中间产物M_(412)动力学过程、质子泵效率及光电响应信号进行了测量。通过与正常紫膜进行比较,可以看出:赖氨酸被修饰后,M_(412)快、慢组分的衰减及质子的吸收过程均减慢,M_(412)和质子的产额、跨膜光电位信号均有不同程度的提高;丝氨酸被修饰后,M_(412)和质子的动力学过程的变化与赖氨酸基本相同,但M_(412)和质子的产额及跨膜光电位提高很大,且光电位出现缓慢反向现象。结果表明赖氨酸不大可能直接参与质子的传递过程,其对紫膜质子泵的影响主要是通过其所带电荷对表面电位的贡献;而丝氨酸却似乎对bR的功能影响很大并对维持质子通道构象环境的稳定起着很大作用。We've measured M412 kinetic process, proton pumping efficiency and photoelectric responses of two kinds of chemical modified bR. Compared with normal Purple Membrane, modification of lysine and serine residues can not only slow down the M412 decay and proton uptake, but also raise the yield of M412, quantum efficiency of proton pumping and photoelectric signals. Moreover, modification of serine may reverse the photopotentials. It seems that lysine residues do not directly participate in the proton translocation process, while serine plays an important role in maintaining the stability of the proton passage, which may strongly affect the proton pumping function of bR.

关 键 词：化学修饰 菌紫质 光化学循环光电位 

分 类 号：Q734[生物学—分子生物学]