Binary flash‐induced oscillations of [14C]DCMU binding to the photosystem II acceptor complex

FEBS Letters

Schreiber, Ulrich¹  Urbach, Wolfgang¹  Laasch, Henrik¹ 

[1] Lehrstuhl für Botanik I, Universität Würzburg, Mittlerer Dallenbergweg 64, D-8700 Würzburg, FRG

关键词: DCMU-binding;    Binary oscillation;    Chlorophyll fluorescence;    Inhibitor binding kinetics;    DCMU;    3-(3;    4-dichlorophenyl)-1;    1-dimethylurea;    HEPES;    n-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid;    MES;    2-(N-morpholino)ethanesulfonic acid;   

DOI  :  10.1016/0014-5793(83)80463-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Binding of radioactively-labelled DCMU to spinach chloroplast membranes is determined following pre-illumination by single turnover saturating light flashes. When binding is assayed rapidly following inhibitor addition (< 40 s) distinct binary oscillations of [¹⁴C]DCMU binding can be observed. By dark-adapted samples or those, following an even number of flashes, more inhibitor is bound than after one or an odd number of flashes. During longer incubation times (2 min), [¹⁴C]DCMU binding becomes independent of flash preillumination. Comparison of the [¹⁴C]DCMU binding kinetics following one flash and the kinetics of the DCMU-induced increase of chlorophyll fluorescence rise reveals a substantial amount of binding which is not accompanied by a corresponding fluorescence rise. These data are discussed within the framework of the ‘inhibitor-plastoquinone competition model’ [FEBS Lett. (1981) 126, 277–281] and with reference to DCMU binding data derived from fluorescence measurements [Biochim. Biophys. Acta (1982) 682, 245–253].

【 授权许可】

Unknown