pH对菌紫质分子的旋转运动和光电响应的影响

用闪光诱导瞬间二向色性方法测量了不同pH条件下的菌紫质分子在脂质囊泡中的旋转扩散运动.在人工平扳膜(BLM)系统中测量了不同pH条件下菌紫质分子的光电响应.在pH3至8.3的范围内没有明显观察到菌紫质分子在膜中旋转运动上的差别.pH低于3时,菌紫质分子旋转运动受到影响;pH高于11时,观察不到旋转扩散运动.在BLM系统中测量了pH2到pH11范围内菌紫质分子的光电响应信号,随着pH的增加,无论紫膜碎片还是单体菌紫质分子的光电响应逐渐由照光后快速正信号并快速衰减及撤光时的快速负信号并逐渐衰减变成慢的正信号.pH高于9.4时,单体菌紫质分子的光电响应信号由正变负,pH高于11时,观察不到信号.

THE EFFECT OF pH ON THE ROTATIONAL DIFFUSION AND PHOTOELECTRICAL RESPONSE OF BACTERIORHODOPSIN

The rotational diffusion of bacteriorhodopsin reconstituted into DMPC vesicles was measured at different pH by the technique of flash-induced transient dichroism.Photoelectrical response of bacteriorhodopsin was measured at different pH by the planar membrane system (BLM).In the range of pH3 to pH 8.3,no obvious difference of the rotational diffusion of bacteriorhodopsin was observed.Below pH3,there was obvious difference.Above pH 11,no rotational diffusion could be observed.In the range of the pH2 to pH 11,we measured photo-electrical response of bacteriorhodopsin of BLM.with the increase of the pH value,both the photoelectrical response of the fragment and monomer of bacteriorhodopsin changed from fast positive signal (light on) and fast negative signal (light off) to slow positive signal.Above pH 9.4,the photoelectical response (light on) of monomer changed from positive to negative.Above pH 11,no-photoelectric response could be observed.