细菌视紫红质光循环中间体M_(412)的动力学初探  

The Primary Research on The Kinetics of The Intermediate M_(412) in The Photocycle of Bacteriorhodopsin

作　　者：陈德亮[1] 王英利[2] 姚保利[2] 胡坤生[1] 

机构地区：[1]中国科学院生物物理研究所,北京100101 [2]中国科学院西安光学精密机械研究所,西安710068

出　　处：《生物化学与生物物理进展》2002年第3期487-490,共4页Progress In Biochemistry and Biophysics

基　　金：国家自然科学基金资助项目 (60 0 0 70 0 9)~~

摘　　要：采用紫外可见吸收光谱技术和闪光光解技术 ,初步观察了细菌视紫红质 (BR)分子在宽 pH范围 (2 1～12 3)内的特征吸收峰以及M412 的相对浓度和M412 的慢成分半衰期的变化 ,并对其结构和光循环功能进行了讨论 .紫外可见吸收光谱实验结果显示 :pH =5 0～ 10 0时 ,BR最大特征吸收峰值约为 5 6 8nm ;pH <5 0时 ,BR最大特征吸收峰发生红移 ;pH >10 0时 ,BR最大特征吸收峰发生蓝移 .闪光动力学光谱结果显示 :pH为7 3～ 9 5时 ,M412 的相对浓度 (M0 )基本稳定在 0 0 38左右 ;pH <7 3时 ,M0 逐渐减小 ;pH >9 5时 ,M0 明显上升 ,在pH =11 8时达到最大值 0 135 5 ,随后又快速下降 .pH为 2 1～ 7 3时 ,M412 的慢成分半衰期 (ts1/2 )值在 (4 1± 1 1)ms左右 ;pH >7 3时 ,ts1/2 值急剧延长到 4 0 6 77 4ms .推测在高 pH条件下 。The changes of bacteriorhodopsin's structure and function were monitored by the UV/VIS absorption spectrum technique and the flash photolysis technique over the wide pH range (2.1similar to12.3). The results of the UV/VIS absorption spectra showed that: 1) the wavelength of the characteristic absorption peak was about 568 nm (PH= 5.0similar to10.0), 2) the red shift of the absorption spectra was observed (pH<5.0) and 3) the blue shift of the absorption spectra was observed ( PH > 10.0). The results of the flash-induced kinetics spectra indicated that: a) M-o (relative concentration of M-412) kept around 0.038 constantly (PH = 7.3similar to9.5); b) Mo decreased gradually as PH was below 7.3; c) when PH was above 9.5, M-o increased obviously and reached the maximum 0.1355 (PH = 11.8) then dropped down sharply; d) t(1/2)(s) (halftime of the slow component of M-412) was (4.1 +/- 1.1) ms approximately (PH= 2.1similar to7.3) and t(1/2)(s) was prolonged to 40 677.4 ms sharply (pH>7.3). It can be concluded that under the condition of high PH, the novel pathway and mechanism of bacteriorhodopsin's photocyle may exist.

关 键 词：细菌视紫红质 光循环中间体M412 动力学 

分 类 号：Q936[生物学—微生物学] Q632