FRID, D and GAL, A and OETTMEIER, W and HAUSKA, G and BERGER, S and OHAD, I (1992) THE REDOX-CONTROLLED LIGHT-HARVESTING CHLOROPHYLL-A/B PROTEIN-KINASE - DEACTIVATION BY SUBSTITUTED QUINONES. JOURNAL OF BIOLOGICAL CHEMISTRY, 267 (36). pp. 25908-25915. ISSN 0021-9258,
Full text not available from this repository.Abstract
The deactivation of the redox-controlled light-harvesting chlorophyll a/b protein kinase of Acetabularia acetabulum and pea thylakoids was studied. Substituted benzoquinone, naphthoquinone, and anthraquinone analogs including mono-, di-, and trihalogenated and/or alkylated quinones, which are known to inhibit the cytochrome b6/f activity, deactivate the kinase in the dark, and prevent its activation in the light. Analogs halogenated at positions 2- or 3- are the most effective deactivators. Increasing the size of the alkyl side chain and/or the number of rings lowers the deactivation effect. The activated state of the pea kinase decays with a t1/2 of 15 min, while the Acetabularia enzyme retains its active state for at least 2 h. The midpoint potential for Acetabularia kinase activity in the dark is 120 +/- 10 mV and is compatible with the involvement of plastoquinone in the kinase activation via reduction of the cytochrome complex. Deactivation of kinase by the analogs inhibiting cytochrome b6/f complex activity and the kinase copurification with the cytochrome b6/f fraction obtained from the Acetabularia thylakoid further support this conclusion. These results indicate that the process of kinase activation/deactivation includes the binding of plastoquinol or quinone analogs by the cytochrome complex and its interaction with the kinase. We propose that the latter process may constitute the rate-limiting step controlling the kinase activation/deactivation kinetics.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | PHOTOSYNTHETIC ELECTRON-TRANSPORT; CYTOCHROME B6/F COMPLEX; PHOTOSYSTEM-II; HALOGENATED 1,4-BENZOQUINONES; CHLOROPLAST PHOSPHOPROTEINS; CHLAMYDOMONAS-REINHARDTII; POLYACRYLAMIDE GELS; THYLAKOID MEMBRANES; STATE TRANSITIONS; BF COMPLEX; |
| Depositing User: | Dr. Gernot Deinzer |
| Last Modified: | 19 Oct 2022 08:44 |
| URI: | https://pred.uni-regensburg.de/id/eprint/54249 |
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