Appearance of the Na+‐motive terminal oxidase in Bacillus FTU grown under three different conditions lowering the Δ̄gmH+ level

FEBS Letters

Skulachev, Vladimir P.¹  Semeykina, Anna L.¹ 

[1] Department of Bioenergetics, A.N. Belozersky Institute of Physico-Chemical-Biology, Moscow State University, Moscow 119899, USSR

关键词: Low ̄gmH+;    Na+ oxidase;    Protometor;    Bacillus FTU;    Δ̄gmH+;    transmembrane difference in electrochemical H+ potential;    Δψ;    transmembrane electric potential difference;    CCCP;    carbonyl cyanide m-chlorophonylhydrazone;    TMPD;    N;    N;    N′;    N′-tetramethyl p-phenylenediamine;   

DOI  :  10.1016/0014-5793(92)80407-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The terminal oxidases and coupled Na⁺ transport have been studied in intact cells and inside-out subcellucar vesicles of alkalo- and halotolerant Bacillus FTU grown under different conditions. Cells grown at pH 7.5 are shown to possess a system or respiration-dependent Na⁺ transport which is (i) inhibited by protonophorous uncoupler and (ii) activated by Δψ-discharging agent valinomycin, suggesting that the Na⁺ transport is due to cooperation of the H⁺-motive oxidase and Na⁺/H⁺ antiporter. On the other hand, growth under conditions lowering the Δ\̄gm_H+ level, namely (i) pH 8.6, (ii) pH 7.5 in the presence of protonophore, and (iii) pH 7.5 in the presence of low cyanide concentrations results in appearance of terminal oxidase-supported Na⁺ transport which is stimulated by protonophores (the Na⁺-motive oxidase). In all three cases, the appearance of ascorbate (+ TMPD) oxidation resistant to low and sensitive to high cyanide concentrations was found to occur. It is concluded that not only alkaline pH but also other conditions which lower Δ\̄gm_H+ can cause substitution of Na⁺ for H⁺ as a coupling ion.

【 授权许可】

Unknown