Next Article in Journal
Highly Active Catalysts for the Dehydration of Isopropanol
Previous Article in Journal
Multi-Leg TiO2 Nanotube Photoelectrodes Modified by Platinized Cyanographene with Enhanced Photoelectrochemical Performance
Open AccessArticle

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

Department of Physics, Gettysburg College, 300 North Washington Street, Gettysburg, PA 17325, USA
*
Author to whom correspondence should be addressed.
Catalysts 2020, 10(6), 718; https://doi.org/10.3390/catal10060718
Received: 5 June 2020 / Revised: 21 June 2020 / Accepted: 23 June 2020 / Published: 26 June 2020
(This article belongs to the Special Issue Photo-Induced Electron Transfer Kinetics in Catalysis)
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. View Full-Text
Keywords: electron transfer kinetics; energy transfer kinetics; photocatalysis; quantum dynamics; photosynthesis; photosystem II; reaction center; tight-binding model; QuAPI electron transfer kinetics; energy transfer kinetics; photocatalysis; quantum dynamics; photosynthesis; photosystem II; reaction center; tight-binding model; QuAPI
Show Figures

Figure 1

MDPI and ACS Style

Sato, Y.; Sicotte, D. Asymmetry in Charge Transfer Pathways Caused by Pigment–Protein Interactions in the Photosystem II Reaction Center Complex. Catalysts 2020, 10, 718.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop