Fitter J, Verclas S A, Lechner R E, Seelert H, Dencher N A
Institut für Biochemie, TU Darmstadt, Germany.
FEBS Lett. 1998 Aug 21;433(3):321-5. doi: 10.1016/s0014-5793(98)00938-7.
By neutron scattering experiments and time-resolved absorption spectroscopy we have investigated picosecond equilibrium fluctuations and the kinetics of the photocycle of bacteriorhodopsin (BR) in the purple membrane (PM). Natural PM samples composed of 75% BR (w/w) and 25% lipid (w/w) as well as delipidated PM having only 5% lipid (w/w) were measured at different levels of hydration. We observed a reduced 'flexibility', due to a diminished weight of stochastic large-amplitude motions occurring in the delipidated PM as compared to the natural PM. This effect is more pronounced for wet samples, indicating the importance of lipid hydration for protein dynamics. The reduced flexibility is accompanied by significantly larger time constants describing the decay of the M-intermediate. Therefore, a correlation between the dynamical behavior of the protein-lipid complex and BR function emerges.
通过中子散射实验和时间分辨吸收光谱，我们研究了紫色膜（PM）中细菌视紫红质（BR）的皮秒级平衡涨落和光循环动力学。在不同水合水平下，对由75%（w/w）的BR和25%（w/w）的脂质组成的天然PM样品以及仅含5%（w/w）脂质的脱脂PM进行了测量。我们观察到，与天然PM相比，脱脂PM中随机大振幅运动的权重减小，导致“柔韧性”降低。这种效应在湿样品中更为明显，表明脂质水合对蛋白质动力学的重要性。柔韧性的降低伴随着描述M中间体衰减的时间常数显著增大。因此，蛋白质-脂质复合物的动力学行为与BR功能之间出现了相关性。
