The Qo site of cytochrome b6f complexes controls the activation of the LHCII kinase

摘要: We created a Qo pocket mutant by site-directed mutagenesis of the chloroplast petD gene in Chlamydomonas reinhardtii. mutated conserved PEWY sequence EF loop subunit IV into PWYE. The pwye did not grow phototrophic conditions although it assembled wild-type levels cytochrome b6f complexes. demonstrated complete block electron transfer through complex and loss plastoquinol binding at Qo. accumulation complexes lacking affinity for enabled us to investigate role activation light-harvesting II (LHCII) kinase during state transitions. detected no fluorescence quenching room temperature relative that I. quantum yield spectrum photosystem I charge separation two displayed trough absorption region major chlorophyll a/b proteins, demonstrating cells remained locked 33Pi labeling phosphoproteins vivo antenna proteins poorly phosphorylated both conditions. Thus, absence transitions demonstrates directly is required LHCII activation.