野生型细菌视紫红质薄膜光谱响应特性的实验研究

细菌视紫红质 (Bacteriorhodopsin ,简称BR)是嗜盐菌细胞膜内的一种光敏蛋白质。BR薄膜材料具有优异的光循环特性和光致变色特性 ,在光信息处理领域中有广阔的应用前景。文章通过紫外 可见光光纤光谱仪测试野生型细菌视紫红质 (BRWT)在经过 5 32nm的YAG激光的泵浦激励后 ,薄膜对探测光的吸收光谱变化情况来着重讨论BRWT的光谱响应特性。采用的样品基态 (B态 )最大吸收波长均为 5 6 2nm ,光密度分别为OD(WT1) 562nm=2 0 4 ,OD(WT2 ) 562nm =1 37。实验结果表明 ,在 5 5 0～ 6 5 0nm波长范围内 ,两个BRWT分子膜对探测光随着探测时间的延长均出现吸收增强的现象。利用双e指数曲线拟合方法分析出 5 5 0～ 6 5 0nm吸收增强的变化过程分为快过程和慢过程 ,其对应的时间常数BRWT1分别约为 11ms和 6 0s ,BRWT2 分别约为 2 4ms和 35s。

Study on the Spectrum Response Characteristic Based on the Wide Type Bacteriorhodopsin Film

The photochromic retinal protein bacteriorhodopsin (BR) was found in the cell membrane of the Archaean Halobacterium salinarium. The excellent photochromic and photocycle properties of the BR provide the possibility of many applications in the filed of optical information processing. In this paper, the spectrum response characteristic of the wild type bacteriorhodopsin molecule film was studied by using pump probe method. After the samples was excited by 532 nm YAG laser beam, the absorption spectra were probed by an optical fiber spectrum analysis (OSA). The absorption peaks at the ground state ( B state) of the two samples are all at 562 nm wavelength. At 562 nm wavelength, the optical densities ( OD ) of the samples are about OD (WT1) 562 nm =2 04 and OD (WT2) 562 nm =1 37 respectively. The experiment results show that BR WT films have absorption that appears to strengthen with the probe time increasing in wavelength 550 650 nm, and this change phenomenon is described by spectra measured at different probe time. Appling the theoretical plot fit of two exponentials to analyze the process of the absorption change it is found that this change includes two processes fast process and slow process. Their corresponse time constants of BR WT1 are about 11 ms and 60 s, and those of BR WT2 about 24 and 30 s respectively.