Bogomolni R A, Spudich J L
Proc Natl Acad Sci U S A. 1982 Oct;79(20):6250-4. doi: 10.1073/pnas.79.20.6250.
Mutant Halobacterium halobium strains deficient in all previously reported rhodopsin-like pigments show phototaxis responses comparable to those of wild-type strains. Spectroscopic analysis reveals the presence of a third retinal-containing pigment in the cells and their membrane fractions. It undergoes a photoreaction cycle with a half-time of approximately equal to 1 sec at room temperature and at physiological light intensities the photostationary state of the pigment consists of two species, one absorbing in the 580- to 590-nm region and the other at 373 nm, both of which are photoactive. Illumination of the long-wavelength species generates the 373-nm intermediate, which upon photoexcitation reconverts to the long-wavelength form. Therefore, changes in the relative light intensities in the long- and short-wavelength regions of the visible spectrum cause opposing shifts in the photostationary state. The spectral sensitivity of this pigment correlates with the color-discriminating phototaxis sensitivities of this organism and strongly suggests that it is the sensory photoreceptor.
缺乏所有先前报道的视紫红质样色素的嗜盐菌突变株表现出与野生型菌株相当的趋光性反应。光谱分析表明，细胞及其膜组分中存在第三种含视黄醛的色素。它在室温下经历光反应循环，半衰期约为1秒，在生理光照强度下，该色素的光稳态由两种物质组成，一种在580至590纳米区域吸收，另一种在373纳米吸收，两者均具有光活性。长波长物质的光照产生373纳米中间体，该中间体在光激发后重新转化为长波长形式。因此，可见光谱长波长和短波长区域相对光强度的变化会导致光稳态产生相反的偏移。这种色素的光谱敏感性与该生物体的颜色辨别趋光性敏感性相关，强烈表明它是感觉光感受器。
