Protein phosphorylation-induced State I-State II transitions are dependent on thylakoid membrane microviscosity.
Incorporation of cholesterol hemisuccinate into thylakoid membranes decreased the membrane fluidity as measured by polarized fluorescence from 1,6-diphenyl-1,3,5-hexatriene. Increasing membrane viscosity in this manner did not inhibit the thylakoid membrane protein kinase. In contrast the effects of the protein phosphorylation on State I-State II transitions, which were observed in untreated membranes, were abolished. This observation is interpreted as indicating that protein phosphorylation-induced energy transfer changes are sensitive to membrane viscosity because they might require a lateral migration of the light-harvesting complex serving Photosystem II from grana to stromal lamellae. Cation effects on room- and low-temperature fluorescence emission properties and membrane adhesion were not abolished in these cholesterol hemisuccinate-treated membranes.
D002736:Chloroplasts / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism; D007700:Kinetics; D008560:Membrane Fluidity; D008565:Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism*; D010766:Phosphorylation; D010788:Photosynthesis; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism*; D010944:Plants / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D014783:Viscosity
D008565:Membrane Proteins; D010940:Plant Proteins; D011494:Protein Kinases