Effects of the molecular environment on some spectroscopic properties of Blepharisma photoreceptor pigment.
Effects of the molecular environment on some spectroscopic properties of Blepharisma photoreceptor pigment.
复制标题
分子环境对 Blepharisma 感光色素某些光谱性质的影响。
DOI：
10.1016/1011-1344(89)80049-1
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
G. Phillips
中科院分区：
文献类型：
--
作者：
F. Lenci;F. Ghetti;D. Gioffrè;V. Passarelli;P. Song;P. F. Heelis;B. Thomas;G. Phillips
在以前的论文[1]中，报道了一些关于Blepharisma japonicum的荧光特性的数据，Blepharisma japonicum是负责光运动反应的光感受器色素。Blepharismin位于细胞外膜下方的深色颗粒中，是一种mesonaphthodianthrone-type分子，与天然光敏剂金丝桃素和Stentor coeruleus的感光色素Stentorin非常相似。在这些实验中，分子环境对色素的光谱行为的影响通过以下事实显示：颗粒包埋的小泡菌素制剂的荧光寿命和荧光量子产率（分别为0.62 ns和0.018）显著低于乙醇溶液中提取的小泡菌素的测量值（分别为1.08 ns和0.036）[1]。由于了解眼睑色素中光敏转导的主要事件如何取决于感光细胞分子基质的性质的重要性[2]，我们正在研究相对简单的模型系统中眼睑色素的光物理和光化学性质。在本初步说明中，我们报告了第一组结果：（i）三重态寿命和三重态-三重态瞬态吸收光谱，以及（ii）溶剂极性和介质碱度对色素某些荧光特性的作用。所有的测量都是在blepharismin粗提物上进行的。因为颜料仅微溶于水，所以在我们的整个实验中使用非水溶液;由于这个原因，不可能评估绝对pH和pK值（特别是pK，将loll-1344/89/$3.50@Elsevier Sequoia/Printed in The Netherlands
In a previous paper [l] some data were reported on the fluorescence characteristics of blepharismin, the photoreceptor pigment responsible for photomotile responses of the ciliated protozoan Blepharisma japonicum. Blepharismin, which is located in deeply coloured granules arranged in rows just beneath the outer cellular pellicle, is a mesonaphthodianthrone-type molecule, rather similar to the natural photosensitizer hypericin and to the photoreceptor pigment of Stentor coeruleus, stentorin. In those experiments, the effect of the molecular environment on the spectroscopic behaviour of the photopigment was shown by the fact that both the fluorescence lifetime and the fluorescence quantum yield of a preparation of granule-embedded blepharismin (0.62 ns and 0.018 respectively) were significantly lower than those measured for extracted blepharismin in ethanol solution (1.08 ns and 0.036 respectively)[l]. Because of the importance of knowing how primary events of photosensory transduction in Blepharisma depend on the nature of the molecular matrix of the photoreceptor [2], we are investigating the photophysical and photochemical properties of blepharismin in relatively simple model systems. In this Preliminary Note we report a first set of results on (i) triplet state lifetimes and triplet-triplet transient absorption spectra of blepharismin and (ii) the role played by both the polarity of the solvent and the basicity of the medium on some fluorescence characteristics of the pigment. All the measurements were performed on blepharismin crude extracts. Because the pigment is only slightly soluble in water, non-aqueous solutions were used throughout our experiments; for this reason it is not possible to evaluate absolute pH and pK, values (in particular pK, would loll-1344/89/$3.50@ Elsevier Sequoia/Printed in The Netherlands