Existence of two L photointermediates of halorhodopsin from Halobacterium salinarium, differing in their protein and water FTIR bands.
Existence of two L photointermediates of halorhodopsin from Halobacterium salinarium, differing in their protein and water FTIR bands.
复制标题
来自盐盐杆菌的盐视紫红质的两种 L 光中间体的存在，其蛋白质和水 FTIR 谱带不同。
DOI：
10.1021/bi9903042
复制
发表时间：
1999
期刊：
影响因子：
2.9
通讯作者：
A. Maeda
中科院分区：
文献类型：
--
作者：
Y. Chon;H. Kandori;J. Sasaki;J. Lanyi;R. Needleman;A. Maeda
记录了来自盐杆菌的盐视紫红质在 170 和 250 K 下的光反应的 FTIR 差异光谱。可见光谱和发色团的 FTIR 谱带均未注意到两个温度下的明显差异。然而，在 250 K 时，在 L 中间体中观察到 Asp141 的扰动，但在 170 K 时未观察到。我们将这些光产物命名为 La（在 170 K 时）和 Lb（在 250 K 时）。 Lb 的光谱与 La 的光谱不同，还表现在水 O-H 伸缩带的不同位移，以及来自蛋白质主链的带对不同卤化物具有不同敏感性的较大变化。这些结果表明，盐视紫红质的光循环包含两种L态，La和Lb，其中蛋白质和内部水分子的结构不同，但氯离子停留在靠近席夫碱的同一位点。
FTIR difference spectra were recorded for the photoreactions of halorhodopsin from Halobacterium salinarium at 170 and 250 K. Obvious differences at the two temperatures were noted in neither the visible spectra nor the FTIR bands of the chromophore. However, perturbation of Asp141 is observed in the L intermediate at 250 K but not at 170 K. We named these photoproducts La (at 170 K) and Lb (at 250 K). The spectrum of Lb is distinct from that of La also in the different shifts of water O-H stretching bands, and larger changes in the bands from the protein backbone with different sensitivities to varying the halide. These results suggest that the photocycle of halorhodopsin contains two L states, La and Lb, in which the structure of protein and internal water molecules is different but chloride stays at the same site close to the Schiff base.