用人工双分子膜(BLM)技术及动力学光谱研究了赖氨酸残基在紫膜的结构和功能中所起的作用.酰化基团与菌紫质(bR)分子中的赖氨酸残基的ε氨基作用,使光照后bR的跨膜质子迁移信号及膜的充放电速度变慢,光循环中间产物M412的产量下降,半衰期延长.但UV/Vis吸收光谱表明酰化并未破坏bR中视黄醛的构象环境.在高pH或高盐浓度下,酰化的影响降低.这些结果表明:赖氨酸残基并不是泵出质子的提供者,没有直接参与质子的跨膜输运,而是通过表面电位来影响bR的质子泵功能.
The role of lvsine residues in the structure and function of bacteriorhodopsin(bR) was studied by the chemical modification method──acetylation. After acetylation, the photoresponse signals and the decay of photocycle intermediate M412 were slowed down while the yields of M412 were decreased. But UV/VIS absorption spectra did not show that the conformation around retinal chromophore was disturbed by acetylation. The effect of acetylation was weakened by high pH or salt media. The results imply that lysine residues do not directly participate in the proton translocation. instead, they affect this process by their contribution to the surface protentials.
胡坤生,施桦,黄莹,余湢.酰化菌紫质的动力学光谱及光电特性研究[J].生物化学与生物物理进展,1994,21(2):150-153
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