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

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.

Author(s):  
Michael R. Wasielewski ◽  
Douglas G. Johnson ◽  
Govindjee ◽  
Christopher Preston ◽  
Michael Seibert

1996 ◽  
Vol 271 (4) ◽  
pp. 2093-2101 ◽  
Author(s):  
Linda B. Giorgi ◽  
Peter J. Nixon ◽  
Stephen A. P. Merry ◽  
D. Melissa Joseph ◽  
James R. Durrant ◽  
...  

2013 ◽  
Vol 15 (7) ◽  
pp. 075013 ◽  
Author(s):  
Andrius Gelzinis ◽  
Leonas Valkunas ◽  
Franklin D Fuller ◽  
Jennifer P Ogilvie ◽  
Shaul Mukamel ◽  
...  

2017 ◽  
Vol 114 (9) ◽  
pp. 2224-2229 ◽  
Author(s):  
Daniel A. Weisz ◽  
Haijun Liu ◽  
Hao Zhang ◽  
Sundarapandian Thangapandian ◽  
Emad Tajkhorshid ◽  
...  

Photosystem II (PSII), a large pigment protein complex, undergoes rapid turnover under natural conditions. During assembly of PSII, oxidative damage to vulnerable assembly intermediate complexes must be prevented. Psb28, the only cytoplasmic extrinsic protein in PSII, protects the RC47 assembly intermediate of PSII and assists its efficient conversion into functional PSII. Its role is particularly important under stress conditions when PSII damage occurs frequently. Psb28 is not found, however, in any PSII crystal structure, and its structural location has remained unknown. In this study, we used chemical cross-linking combined with mass spectrometry to capture the transient interaction of Psb28 with PSII. We detected three cross-links between Psb28 and the α- and β-subunits of cytochrome b559, an essential component of the PSII reaction-center complex. These distance restraints enable us to position Psb28 on the cytosolic surface of PSII directly above cytochrome b559, in close proximity to the QB site. Protein–protein docking results also support Psb28 binding in this region. Determination of the Psb28 binding site and other biochemical evidence allow us to propose a mechanism by which Psb28 exerts its protective effect on the RC47 intermediate. This study also shows that isotope-encoded cross-linking with the “mass tags” selection criteria allows confident identification of more cross-linked peptides in PSII than has been previously reported. This approach thus holds promise to identify other transient protein–protein interactions in membrane protein complexes.


2017 ◽  
Vol 19 (7) ◽  
pp. 5195-5208 ◽  
Author(s):  
Vladimir I. Novoderezhkin ◽  
Elisabet Romero ◽  
Javier Prior ◽  
Rienk van Grondelle

A mixing of the exciton and charge transfer states promoted by a resonant vibrational quantum allows faster penetration of excitation energy into the primary photoproduct in the photosystem II reaction center both in laser experiment and under natural conditions.


Sign in / Sign up

Export Citation Format

Share Document