Time‐course and stoichiometry of light‐induced proton release and uptake during the photocycle of bacteriorhodopsin

FEBS Letters

Dencher, Norbert A.¹  Grzesiek, Stephan¹ 

[1] Biophysics Group, Department of Physics, Freie Universität Berlin, Arnimallee 14, D-1000 Berlin 33, Germany

关键词: Bacteriorhodopsin Proton pump Purple membrane pH-indicator Pyranine Flash spectroscopy;   

DOI  :  10.1016/0014-5793(86)81045-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The kinetics and stoichiometry of light-induced proton release in purple membrane suspensions have been investigated using the pH-indicator dye pyranine and single-turnover flash spectroscopy at a time resolution of 0.1 μs. The number of protons detected by pyranine is inversely proportional to the buffering power of the medium and 1.1 ± 0.2 protons are released per photocycling bacteriorhodopsin molecule (pH 7.0, 20°C). At high ionic strength (250 mM KCl) and higher phosphate buffer concentrations (1 mM) the proton release lags slightly behind the formation of the intermediate M-412 and proton reuptake by the purple membrane parallels the slow decay process of M-412 or the decay of O-640.

【 授权许可】

Unknown