Annihilation Processes in the Isolated D1-D2-cyt-b559 Reaction Center Complex of Photosystem II. An Intensity-Dependence Study of Femtosecond Transient Absorption†,‡

1996 ◽  
Vol 100 (22) ◽  
pp. 9537-9544 ◽  
Author(s):  
M. G. Müller ◽  
M. Hucke ◽  
M. Reus ◽  
A. R. Holzwarth
Keyword(s):  
Photosystem Ii ◽  
Reaction Center ◽  
Transient Absorption ◽  
Intensity Dependence ◽  
Femtosecond Transient Absorption ◽  
Reaction Center Complex

scholarly journals Asymmetry in Charge Transfer Pathways Caused by Pigment–Protein Interactions in the Photosystem II Reaction Center Complex

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 718
Author(s):  
Yoshihiro Sato ◽  
Danielle Sicotte
Keyword(s):  
Charge Transfer ◽  
Photosystem Ii ◽  
Reaction Center ◽  
Protein Interactions ◽  
Energy Levels ◽  
Tight Binding ◽  
Relative Displacement ◽  
Primary Charge Separation ◽  
Binding Model ◽  
Reaction Center Complex

This article discusses the photoinduced charge transfer (CT) kinetics within the reaction center complex of photosystem II (PSII RC). The PSII RC exhibits a structural symmetry in its arrangement of pigments forming two prominent branches, D1 and D2. Despite this symmetry, the CT has been observed to occur exclusively in the D1 branch. The mechanism to realize such functional asymmetry is yet to be understood. To approach this matter, we applied the theoretical tight-binding model of pigment excitations and simulated CT dynamics based upon the framework of an open quantum system. This simulation used a recently developed method of computation based on the quasi-adiabatic propagator path integral. A quantum CT state is found to be dynamically active when its site energy is resonant with the exciton energies of the PSII RC, regardless of the excitonic landscape we utilized. Through our investigation, it was found that the relative displacement between the local molecular energy levels of pigments can play a crucial role in realizing this resonance and therefore greatly affects the CT asymmetry in the PSII RC. Using this mechanism phenomenologically, we demonstrate that a near 100-to-1 ratio of reduction between the pheophytins in the D1 and D2 branches can be realized at both 77 K and 300 K. Our results indicate that the chlorophyll Chl D 1 is the most active precursor of the primary charge separation in the D1 branch and that the reduction of the pheophytins can occur within pico-seconds. Additionally, a broad resonance of the active CT state implies that a large static disorder observed in the CT state originates in the fluctuations of the relative displacements between the local molecular energy levels of the pigments in the PSII RC.

scholarly journals Accumulation of the D2 Protein Is a Key Regulatory Step for Assembly of the Photosystem II Reaction Center Complex inSynechocystisPCC 6803

2004 ◽  
Vol 279 (47) ◽  
pp. 48620-48629 ◽  
Author(s):  
Josef Komenda ◽  
Veronika Reisinger ◽  
Bernd Christian Müller ◽  
Marika Dobáková ◽  
Bernhard Granvogl ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Reaction Center ◽  
Reaction Center Complex ◽  
D2 Protein
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