The Physiological Function of the Qc Site in Photosystem II

To identify the physiological function of the Qc site in Photosystem II, several Cyt b559 and PsbJ mutant cells with mutations on and near the Qc site were constructed using the model cyanobacterium Synechocystis sp. PCC 6803. Several mutant cells showed enhanced effects of state transitions under medium blue light and weakened effects of blue-light-induced NPQ under strong blue-light conditions. The results suggest that the Qc site may modulate the short-term light response in cyanobacteria. In addition, photosynthetic growth rate and biomass production were greater for these mutant cells than WT under normal growth conditions. These mutant cyanobacteria can be applied to enhance the productions of biofuels or other valuable commercial products. This work was published in Biochemistry; USA, China and Taiwan patents are pending.