B-Side Charge Separation in Bacterial Photosynthetic Reaction Centers:  Nanosecond Time Scale Electron Transfer from HB-to QB†

Biochemistry ◽  
2003 ◽  
Vol 42 (7) ◽  
pp. 2016-2024 ◽  
Author(s):  
Christine Kirmaier ◽  
Philip D. Laible ◽  
Deborah K. Hanson ◽  
Dewey Holten
Keyword(s):  
Electron Transfer ◽  
Time Scale ◽  
Charge Separation ◽  
Reaction Centers ◽  
Photosynthetic Reaction Centers ◽  
Nanosecond Time Scale

scholarly journals Excitonic structure and charge separation in the heliobacterial reaction center probed by multispectral multidimensional spectroscopy

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yin Song ◽  
Riley Sechrist ◽  
Hoang H. Nguyen ◽  
William Johnson ◽  
Darius Abramavicius ◽  
...  
Keyword(s):  
Reaction Center ◽  
Charge Separation ◽  
Electronic Spectroscopy ◽  
Spectroscopic Studies ◽  
Primary Electron ◽  
Reaction Centers ◽  
Separation Mechanism ◽  
Photosynthetic Reaction Centers ◽  
Density Analysis ◽  
Function Relationship

AbstractPhotochemical reaction centers are the engines that drive photosynthesis. The reaction center from heliobacteria (HbRC) has been proposed to most closely resemble the common ancestor of photosynthetic reaction centers, motivating a detailed understanding of its structure-function relationship. The recent elucidation of the HbRC crystal structure motivates advanced spectroscopic studies of its excitonic structure and charge separation mechanism. We perform multispectral two-dimensional electronic spectroscopy of the HbRC and corresponding numerical simulations, resolving the electronic structure and testing and refining recent excitonic models. Through extensive examination of the kinetic data by lifetime density analysis and global target analysis, we reveal that charge separation proceeds via a single pathway in which the distinct A0 chlorophyll a pigment is the primary electron acceptor. In addition, we find strong delocalization of the charge separation intermediate. Our findings have general implications for the understanding of photosynthetic charge separation mechanisms, and how they might be tuned to achieve different functional goals.

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