FEBS Letters | |
Cl−‐dependent photovoltage responses of bacteriorhodopsin: comparison of the D85T and D85S mutants and wild‐type acid purple form | |
Kalaidzidis, Inna V1  Kaulen, Andrey D1  | |
[1] Department of Photobiochemistry, A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119899 Moscow, Russia | |
关键词: Bacteriorhodopsin; Photocycle; Photovoltage response; Cl− transport; D85S and D85T mutants; Halobacterium salinarium; bR; bacteriorhodopsin; hR; halorhodopsin; PM; purple membrane; | |
DOI : 10.1016/S0014-5793(97)01390-2 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
Laser flash-induced photovoltage responses of the D85S and D85T mutants as well as of the wild-type acid blue form are similar and reflect intraprotein charge redistribution caused by retinal isomerization. The Cl−-induced transition of all of these blue forms into purple ones is accompanied by the appearance of electrogenic stages, which is probably associated with Cl− translocation in the cytoplasmic direction. Cl− translocation efficiency of these purple forms is much lower than that of the proton transport by the wild-type bacteriorhodopsin. The values of the efficiency do not exceed 15, 8 and 3% for the D85T, D85S and wild-type acid purple form, respectively. Cl− induces an additional electrogenic phase in the photovoltage responses of the D85S mutant and the wild-type acid purple form. This phase is supposed to be associated with the reversible Cl− movement in the extracellular direction. It is interesting that this component is absent in the photovoltage response of the D85T mutant which has, like halorhodopsin, a threonine residue at position 85.
【 授权许可】
Unknown
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