Studies on kinase-controiled state transitions in Photosystem II and $b_6 f$ mutants from $Chlamydomonas\ reinhardtii$ which lack quinone-binding proteins

Francis-André Wollman (1) , Claire Lemaire (1)

1 IBPC (FR_550) - Institut de biologie physico-chimique

We have studied kinase-dependent state transitions in vivo using photosynthetic mutants from the green alga $Chlamydomonas\ reinhardtii$ lacking in quinone-binding proteins. The aim of our study was to identify proteins involved in the plastoquinone-dependent activation of the LHC-kinase. Whereas mutants totally devoid of the quinone-binding subunits D1 and D2 of Photosystem II showed unaltered state transitions, mutants lacking the $b_6 f$ complexes were incapable of state transitions. These mutants were blocked in State 1, which is indicative of either the absence of the LHC-kinase responsible for the regulation, or of the loss of a component responsible for the activation of this enzyme. These two hypotheses are discussed in light of (i) the patterns of phosphorylation of the thylakoid membrane proteins observed in the $b_6 f$ mutants and (ii) the characteristics of the kinase activities recovered from their thylakoids.

Keywords: LHC-kinase; $b_6f$ complex; State 1-State 2 transition; Plastoquinone pool; oxidized/reduced; (Chlamydomonas reinhardtii)

Domains: Life Sciences [q-bio]

Francis-André Wollman, Claire Lemaire. Studies on kinase-controiled state transitions in Photosystem II and $b_6 f$ mutants from $Chlamydomonas\ reinhardtii$ which lack quinone-binding proteins. Biochimica biophysica acta (BBA) - Bioenergetics, 1988, 993 (1), pp.85-94. ⟨10.1016/0005-2728(88)90058-8⟩. ⟨cea-02931671⟩