Novel multipulse saturation spectroscopy for quantum yield determination of charge separation in modified photosynthetic reaction centers

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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Determination of the primary charge separation rate in isolated photosystem II reaction centers with 500-fs time resolution

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.86.2.524 ◽

1989 ◽

Vol 86 (2) ◽

pp. 524-528 ◽

Cited By ~ 123

Author(s):

M. R. Wasielewski ◽

D. G. Johnson ◽

M. Seibert ◽

Govindjee

Keyword(s):

Photosystem Ii ◽

Time Resolution ◽

Charge Separation ◽

Reaction Centers ◽

Primary Charge Separation ◽

Separation Rate

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Excitonic Structure and Charge Separation in the Heliobacterial Reaction Center Probed by Multispectral Multidimensional Spectroscopy

10.26434/chemrxiv.13519169.v1 ◽

2021 ◽

Author(s):

Yin Song ◽

Riley Sechrist ◽

Hoang Huy Nguyen ◽

William Johnson ◽

Darius Abramavičius ◽

...

Keyword(s):

Reaction Center ◽

Charge Separation ◽

Electronic Spectroscopy ◽

Spectroscopic Studies ◽

Primary Electron ◽

Reaction Centers ◽

Separation Mechanism ◽

Photosynthetic Reaction Centers ◽

Density Analysis ◽

Function Relationship

Photochemical 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 initial excited state and 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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