Identification of a proteolipid oligomer as a constituent part of CF0, the proton channel of the chloroplast ATP synthase

FEBS Letters

Junge, Wolfgang¹  Lill, Holger¹ 

[1] Biophysik, Fachbereich Biologie/Chemie, Universität Osnabrück, Postfach 4469, 4500 Osnabrück, FRG

关键词: Photosynthesis;    Photophosphorylation;    Proteolipid;    ATP synthase;    Proton channel;    CF0CF1;    CF1;    chloroplast ATP synthase;    soluble portion;    CF0;    chloroplast ATP synthase;    membrane portion;    DCCD;    N;    N′-dicyclohexylcarbodiimide;    PMS;    phenazinemethosulfate;    SDS;    sodium dodecyl sulfate;    PAGE;    polyacrylamide gel electrophoresis;   

DOI  :  10.1016/0014-5793(89)81152-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We studied the action of the photophosphorylation inhibitor, N,N′-dicyclohexylcarbodiimide (DCCD) on the channel portion (CF₀) of the chloroplast ATP synthase (CF₀CF₁). We found that the target for binding of [¹⁴C]DCCD was an oligomer of the small proteolipid-subunit (subunit III) of CF₀. We treated thylakoids with low concentrations of DCCD, sufficient to inhibit photophosphorylation. The ¹⁴C-labelled inhibitor was found on polyacrylamide gels in a position corresponding to an apparent molecular mass of 50 kDa. This band comprised a homooligomer of proteolipid subunits of CF₀. At higher concentrations of DCCD, it fell apart into proteolipid monomers. This dissociation was prevented by the presence of venturicidin, another CF₀ inhibitor acting on the proteolipid subunit, during the incubation with DCCD. The existence of such an oligomeric substructure in CF₀ is discussed in the light of diverging structural models for the proton channel of F₀F₁-type ATPases.

【 授权许可】

Unknown