Tsuda M, Govindjee R, Ebrey T G
Biophys J. 1983 Nov;44(2):249-54. doi: 10.1016/S0006-3495(83)84296-9.
The effects of pressure and temperature on the decay kinetics of the M412 (M) intermediate in the photocycle of bacteriorhodopsin were studied to provide information about the phase transitions of the purple membrane lipids. The activation volume (delta V++) for the decay of M is expected to be different below and above a phase transition. However, no abrupt change in delta V++ was found from 3.5 degrees to 60 degrees C. But a sharp break was observed in a plot of the logarithm of the rate of M decay vs. pressure. Extrapolation of this break point to standard atmospheric pressure gives a temperature of -42 degrees C, which probably corresponds to the phase transition of the purple membrane lipids. This conclusion is supported by studies of the effect of pressure on the M kinetics of bacteriorhodopsin incorporated into dimyristoylphosphatidylcholine vesicles, whose phase transition has previously been characterized.
研究了压力和温度对细菌视紫红质光循环中M412(M)中间体衰变动力学的影响,以提供有关紫膜脂质相变的信息。预计在相变温度以下和以上,M衰变的活化体积(ΔV++)会有所不同。然而,在3.5摄氏度至60摄氏度范围内未发现ΔV++有突然变化。但是,在M衰变速率的对数与压力的关系图中观察到一个急剧的转折点。将该转折点外推到标准大气压得到的温度为-42摄氏度,这可能对应于紫膜脂质的相变。将细菌视紫红质掺入二肉豆蔻酰磷脂酰胆碱囊泡中的M动力学的压力效应研究支持了这一结论,该囊泡的相变此前已得到表征。