Proton coupling is preserved in membrane‐bound chloroplast ATPase activated by high concentrations of tentoxin

FEBS Letters

Sigalat, Claude¹  Pitard, Bruno¹  Haraux, Francis¹ 

[1] Section de Bioénergétique, DBCM-CEA Saclay, bât. 532, 91191 Gif-sur-Yvette Cedex, France

关键词: F0F1 H+-ATPase;    Proton pump;    Tentoxin;    Inhibitor;    Thylakoid;    Proteoliposome;    9-AA;    9-aminoacridine;    BR;    bacteriorhodopsin;    Chl;    chlorophyll;    transmembrane difference in proton electrochemical potential (electrochemical proton gradient);    ΔpH;    transmembrane pH difference;    DTT;    dithiothreitol;    CF0CF1;    chloroplast ATP synthase (H+-ATPase);    (C)F0;    membranous sector of the H+-ATPase;    (C)F1;    extrinsic;    catalytic sector of the H+-ATPase;    MES;    2(N-morpholino)ethanesulfonic acid;    PS1;    photosystem 1;    Tricine;    N-[2-hydroxy-1;    1-bis(hydroxymethyl)ethyl]glycine;    TTX;    tentoxin;    VTCD;    venturicidin;    Enzyme;    ATP synthase (EC 3.6.1.3);   

DOI  :  10.1016/0014-5793(95)00664-U

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The effect of tentoxin at high concentrations was investigated in thylakoids and proteoliposomes containing bacteriorhodopsin and CF₀CF₁. Venturicidin-sensitive ATP hydrolysis, ATP-generated ΔpH and ATP synthesis were practically 100% inhibited at 2 μM tentoxin, and restored to various extents beyond 50 μM. With respect to the native enzyme, tentoxin-reactivated ATPase had the following properties: (i) a higher ΔpH requirement to synthetise ATP; (ii) a decreased futile proton flow through CF₀CF₁ (without ADP), which remains 100% blocked by ADP. It is concluded that despite its altered kinetic performances, tentoxin-modified CF₀CF₁ preserves its mechanism and remains a tightly coupled proton pump.

【 授权许可】

Unknown