Density Functional Studies of the Spin Density Distribution of the P865 Cation Radical in the Reaction Center ofRb sphaeroides

Biochemistry ◽  
2008 ◽  
Vol 47 (50) ◽  
pp. 13261-13266 ◽  
Author(s):  
Benjamin Robotham ◽  
Patrick J. O’Malley
2020 ◽  
Author(s):  
Denis Artiukhin ◽  
Patrick Eschenbach ◽  
Johannes Neugebauer

We present a computational analysis of the spin-density asymmetry in cation radical states of reaction center models from photosystem I, photosystem II, and bacteria from Synechococcus elongatus, Thermococcus vulcanus, and Rhodobacter sphaeroides, respectively. The recently developed FDE-diab methodology [J. Chem. Phys., 148 (2018), 214104] allowed us to effectively avoid the spin-density overdelocalization error characteristic for standard Kohn–Sham Density Functional Theory and to reliably calculate spin-density distributions and electronic couplings for a number of molecular systems ranging from inner pairs of (bacterio)chlorophyll a molecules in vacuum to large protein including up to about 2000 atoms. The calculated spin densities show a good agreement with available experimental results and were used to validate reaction center models reported in the literature. Here we demonstrate that the applied theoretical approach is very sensitive to changes in molecular structures and relative orientation of molecules. This makes FDE-diab a valuable tool for electronic structure calculations of large photosynthetic models effectively complementing the existing experimental techniques.<br>


2020 ◽  
Author(s):  
Denis Artiukhin ◽  
Patrick Eschenbach ◽  
Johannes Neugebauer

We present a computational analysis of the spin-density asymmetry in cation radical states of reaction center models from photosystem I, photosystem II, and bacteria from Synechococcus elongatus, Thermococcus vulcanus, and Rhodobacter sphaeroides, respectively. The recently developed FDE-diab methodology [J. Chem. Phys., 148 (2018), 214104] allowed us to effectively avoid the spin-density overdelocalization error characteristic for standard Kohn–Sham Density Functional Theory and to reliably calculate spin-density distributions and electronic couplings for a number of molecular systems ranging from inner pairs of (bacterio)chlorophyll a molecules in vacuum to large protein including up to about 2000 atoms. The calculated spin densities show a good agreement with available experimental results and were used to validate reaction center models reported in the literature. Here we demonstrate that the applied theoretical approach is very sensitive to changes in molecular structures and relative orientation of molecules. This makes FDE-diab a valuable tool for electronic structure calculations of large photosynthetic models effectively complementing the existing experimental techniques.<br>


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