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(␮-O) 2 in superoxidized manganese catalase has been suggested as the basis for inactivity of this oxidation state; G. argued against a Mn valence change on S 2 3 S 3 , and Yachandra et al. (4) have proposed that one-electron oxidation of the bridging oxo group (or groups) occurs. However, a similar bridging oxyl ligand formulation for intermediate X in(More)
The set up described in Steffen et al. (Biochemistry 40:173-180, 2001) was used to monitor in the time domain from 100 ns to 10 s single turnover flash-induced transients of the normalized fluorescence yield (SFITFY) on dark-adapted cells of the thermophilic algae Chlorella pyrenoidosa Chick. Perfect data fit was achieved within the framework of a(More)
Our recently presented PS II model (Belyaeva et al., 2008) was improved in order to permit a consistent simulation of Single Flash Induced Transient Fluorescence Yield (SFITFY) traces that were earlier measured by Steffen et al. (2005) on whole leaves of Arabidopsis (A.) thaliana at four different energies of the actinic flash. As the essential(More)
Oxidative photosynthetic water cleavage into molecular oxygen and four protons occurs via a sequence of redox steps that are energetically driven by the strongly oxidizing cation radical P +. . This species formed as a result of light-induced charge separation in Photosystem II becomes reduced by Y Z thus generating ox Z Y that in turn oxidizes stepwise the(More)
The thermal blockage of QA-. oxidation was analysed in PS II membrane fragments by monitoring flash-induced changes of the relative fluorescence quantum yield as a function of temperature. The results obtained reveal: (a) in dark-adapted samples the fraction of QA-. that is not reoxidised within a time domain of 10 s after the actinic flash increases with(More)
Oscillation patterns of the oxygen yield per flash induced by a train of single-turnover flashes were measured as a function of dark incubation and different pre-illumination conditions in several autotrophic mutant strains of Synechocystis sp. PCC 6803 carrying short deletions within the large, lumen-exposed hydrophilic region (loop E) of the chlorophyll(More)
A detailed kinetic analysis is presented for the pH dependence of the reduction of the water-oxidizing complex (WOC) in redox state S1 by hydrophilic amines NH2R (R = NH2, OH) in suspensions of isolated thylakoids. Measurements of patterns of the oxygen yield induced by a train of single-turnover flashes and evaluation of the data within the framework of an(More)
DISSERTATION zur Erlangung des akademischen Grades d o c t o r r e r u m n a t u r a l i u m Abstract Transient four-wave-mixing experiments with femtosecond resolution are performed in order to investigate phase and energy relaxation processes of optically excited states in the light harvesting complex II of higher plants (LHC II) and in the semiconductor(More)
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