Photochromic kinetic spectra and intermediates of BR-D96N  

作　　者：郑媛 姚保利 王英利 雷铭 陈国夫 Norbert Hampp 

机构地区：[1]State Key Laboratory of Transient Optics Technology,Xi'an Institute of Optics and Precision Mechanics,Chinese Academy of Sciences,Xi'an 710068,China [2]Institute for Physical Chemistry,University of Marburg,D-35032 Marburg,Germany

出　　处：《Science China(Physics,Mechanics & Astronomy)》2003年第1期1-7,共7页中国科学：物理学、力学、天文学（英文版）

基　　金：the National Natural Science Foundation of China(Grant No.60007009);the President Foundation of Chinese Academy of Sciences(Grant No.40007059)

摘　　要：BR-D96N is a kind of genetically site-specific mutant of bacteriorhodopsin (BR) with obvious photochromic effect. Compared to the wild type BR, the lifetime of M state of BR-D96N is prolonged to several minutes so that the photochromic kinetics and the intermediates formation can be studied by the conventional spectra analysis. In the experiment, the absorption spectra of the sample at different time after light illumination are measured with spectrophotometer. By fitting and analyzing the variation of the spectra, we suppose there are three main states in the photochromic process, i.e. B state (light-adapted state), M state and D state (dark-adapted state). The absorption spectra of the B state, M state and D state are extracted from the experimental data based on this three-state model and the spectra at various time are fitted with the least square method. So, the variations of population percentages of the M state, B state and D state are obtained and the M state and B state lifetimes are estimated. In another way, from measuring the absorption dynamics at 407 nm and 568 nm, the M state and B state lifetimes are also obtained by two exponential data fitting, which give coincident results with those of the spectra analysis.BR-D96N is a kind of genetically site-specific mutant of bacteriorhodopsin (BR) with obvious photochromic effect. Compared to the wild type BR, the lifetime of M state of BR-D96N is prolonged to several minutes so that the photochromic kinetics and the intermediates formation can be studied by the conventional spectra analysis. In the experiment, the absorption spectra of the sample at different time after light illumination are measured with spectrophotometer. By fitting and analyzing the variation of the spectra, we suppose there are three main states in the photochromic process, i.e. B state (light-adapted state), M state and D state (dark-adapted state). The absorption spectra of the B state, M state and D state are extracted from the experimental data based on this three-state model and the spectra at various time are fitted with the least square method. So, the variations of population percentages of the M state, B state and D state are obtained and the M state and B state lifetimes are estimated. In another way, from measuring the absorption dynamics at 407 nm and 568 nm, the M state and B state lifetimes are also obtained by two exponential data fitting, which give coincident results with those of the spectra analysis.

关 键 词：BR-D96N  photochromic  thermal relaxation  ABSORPTION spectra. 

分 类 号：O433[机械工程—光学工程]