Evidence for a high proton translocation stoichiometry of the H+‐ATPase complex in well coupled proteoliposomes reconstituted from a thermophilic cyanobacterium

FEBS Letters

Kraayenhof, R.¹  Krab, K.¹  van Walraven, H.S.¹  Haak, N.P.¹ 

[1] Biological Laboratory, Vrije Universiteit, De Boelelaan 1087, 1081 HV Amsterdam, The Netherlands

关键词: ATPase proteoliposome Energy transduction Protonmotive force Diffusion potential Phosphate potential Proton translocation stoichiometry;   

DOI  :  10.1016/0014-5793(86)81548-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Evidence is presented for a high proton translocation stoichiometry (H+/ATP) of approx. 9 in ATPase proteoliposomes with extremely low permeability for ions, reconstituted from a thermophilic cyanobacterium. A proportional relation between the phosphate potential (ΔG _fp) and the proton-motive force (Δp) was observed in thermodynamic equilibrium. A bulk-to-bulk Δp was imposed by valinomycin-induced K⁻ diffusion potentials of different size while the initial ΔG _fp was varied. In all cases equilibrium was reached in about 1.5 h. A high H⁻/ATP ratio was also deduced from the relation between the initial rates of ATP synthesis or hydrolysis at varying ΔG _fp and Δp. The implications of these results for the mechanism of energy transduction in energy-conserving membranes are discussed.

【 授权许可】

Unknown