Action spectrum and quantum efficiency for proton pumping in Halobacterium halobium.
Action spectrum and quantum efficiency for proton pumping in Halobacterium halobium.
复制标题
盐杆菌质子泵浦的作用谱和量子效率。
作者：
R. Bogomolni;R. A. Baker;R. Lozier;W. Stoeckenius
盐生盐杆菌的质子射出的作用光谱和量子效率(Phi H+)是在选择的条件下被选择的，以最大限度地减少光触发的质子内流，这通常是在完整的细胞中观察到的。含有类胡萝卜素的菌株R1的作用光谱表明，类胡萝卜素吸收的光能对质子喷射没有贡献。经过类胡萝卜素和其他细胞色素的屏蔽校正后，作用光谱与细菌红素的吸收光谱密切相关。盐生H.halobium细胞和细胞膜中的Phi H+的测定值在0.4到0.7之间。这些值明显高于目前公认的细菌视紫红质在分离的紫膜光反应循环中的量子效率值，这表明至少在完整的细胞和包膜中，在细菌视紫红质的光循环中有不止一个质子被泵浦。在这项工作中使用了一种新的无损检测细菌素的方法，该方法在完整的细胞和也包含其他色素的信封中进行。
The action spectrum and quantum efficiency (phi H+) for proton ejection from Halobacterium halobium have been determined under conditions chosen to minimize light-triggered proton influx which is usually observed in intact cells. The action spectrum for the carotenoid-containing strain, R1, shows that light energy absorbed by the carotenoids does not contribute to the proton ejection. After correction for shielding by the carotenoids and other cell pigments, the action spectrum closely follows the absorption spectrum of bacteriorhosopsin. Values determined for phi H+ in H. halobium cells and cell envelopes range from 0.4 to 0.7. These values are significantly higher than the currently accepted value for the quantum efficiency for the photoreaction cycle of bacteriorhodopsin in isolated purple membrane, suggesting that at least in intact cells and envelopes more than one proton is pumped during the bacteriorhodopsin photocycle. A new nondestructive assay for bacteriorhopopsin in intact cells and envelopes which also contain other pigments was used in this work.