Light-induced changes of absorbance and electron spin resonance in small photosystem II particles.

摘要: Photosystem II reaction center components have been studied in small system particles prepared with digitonin. Upon illumination the reduction of primary acceptor was indicated by absorbance changes due to a plastoquinone semiquinone anion and blue shifts absorption bands near 545 nm (C550) 685 nm. The chlorophyll ratio between 1/20 1/70 various preparations. terminal electron donor this did not cause large but its oxidized form revealed hitherto unknown spin resonance (ESR) signal, which had some properties well-known signal linewidth g-value much nearer those I. darkening ESR decayed together cyclic or back stimulated 3-(3,4 dichlorophenyl)-1,1-dimethylurea. could be ferricyanide dark. Illumination presence induced changes, rapidly reversed upon darkening, may ascribed oxidation dimer, possibly photosystem II. In addition an 15 20 gauss slower dark decay observed, caused secondary donor.