Selective interaction of valinomycin/K+ with the cytochrome bf complex of chloroplasts

FEBS Letters

Klughammer, Christof¹  Schreiber, Ulrich¹ 

[1] Julius-von-Sachs-Institut, Lehrstuhl Botanik I, Universität Würzburg, Mittlerer Dallenbergweg 64, D-97082 Würzburg, Germany

关键词: Cytochrome bf complex;    Q-cycle;    Valinomycin;    MOA stilbene;    Cytochrome b 563 reduction;    DBMIB;    2;    5-dibromo-3-methyl-6-isopropyl-p-benzoquinone;    MOA stilbene;    E-β-methoxyacrylat-stilbene;    NQNO;    2-n-nonyl-4-hydroxyquinoline-N-oxide;    Qp-site;    plastoquinol binding site at electrically positive;    lumen oriented side of the thylakoid membrane;    Qn-site;    plastoquinone binding site at electrically negative;    stroma oriented side of the thylakoid membrane;   

DOI  :  10.1016/0014-5793(93)80862-O

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Valinomycin/K⁺ is shown to selectively interact at sub-micromolar concentrations with the cytochrome bf complex in thylakoid membranes, inducing a red shift of the ferrohaem b absorbance α-band, a slow down of post-illumination β-reoxidation and a corresponding increase of β-reduction level in continuous light. These effects of valinomycin/K⁺ are not related to its field dissipating action, as they are not affected by nonactin. Presence of K⁺ is required. Phenomenologically the valinomycm/K⁺ effects are similar to those caused by 10 times higher MOA stilbene concentrations. However, synergism is observed between the two inhibitors, suggesting different modes of action. When both inhibitors are combined more than one haem b can be reduced by illumination.

【 授权许可】

Unknown