Quantitative evaluation of the dynamics of proton transfer from photoactivated bacteriorhodopsin to the bulk

FEBS Letters

Nachliel, E.¹  Gutman, M.¹ 

[1] Laser Laboratory for Fast Reactions in Biology, Department of Biochemistry, Tel Aviv University, Ramat Aviv 69978, Israel

关键词: Dynamics;    Proton transfer;    Photoactivated bacteriorhodopsin;    BR;    bacteriorhodopsin;    Flu;    ionized states of fluorescein;    FluH;    protonated states of fluorescein;    øO−;    ionized states of 8-hydroxypyrene-1;    3;    6-trisulfonate;    øOH;    protonated states of 8-hydroxypyrene-1;    3;    6-trisulfonate;    COOCP −;    the carboxylic groups on the cytoplasmic;    COOEC −;    extracellular face of the membrane;   

DOI  :  10.1016/0014-5793(96)00870-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

It has been reported by many research groups that protons released during the photocycle of bacteriorhodopsin are detected by surface bound indicators much faster than by indicators in the bulk. In this study we used numerical simulation of chemical reaction's dynamics for analyzing the delayed appearance of protons in the bulk. The results indicate that the low pK surface groups of the membrane, which form an undilutable concentrated matrix of proton binding sites, retain the protons in this space according to the mass action law. The main sites for proton accumulation are the cluster of carboxylates on the cytoplasmic side of the membrane. The protonation of an indicator in the bulk does not proceed by its reaction with free proton, but rather through self-diffusion of the indicator to the membrane and abstraction of proton from the protonated surface group. The detailed mechanisms which correspond with these reactions are reported.

【 授权许可】

Unknown