Theoretical analysis of the electronic asymmetry of the special pair in the photosynthetic reaction center: Effect of structural asymmetry and protein environment

2007 ◽  
Vol 447 (4-6) ◽  
pp. 324-329 ◽  
Author(s):  
Hideki Yamasaki ◽  
Haruki Nakamura ◽  
Yu Takano
Keyword(s):  
Theoretical Analysis ◽  
Reaction Center ◽  
Photosynthetic Reaction Center ◽  
Structural Asymmetry ◽  
Special Pair ◽  
Center Effect ◽  
Protein Environment

Co-facial magnesium porphyrin dimer complexed with fullerene: photosynthetic reaction center model of 'special pair' self-assembled to electron acceptor

2008 ◽  
Vol 12 (07) ◽  
pp. 857-865 ◽  
Author(s):  
Atula S. D. Sandanayaka ◽  
Navaneetha K. Subbaiyan ◽  
Raghu Chitta ◽  
Yasuyuki Araki ◽  
Osamu Ito ◽  
...  
Keyword(s):  
Reaction Center ◽  
Electron Acceptor ◽  
Photosynthetic Reaction Center ◽  
Ammonium Cation ◽  
Model Systems ◽  
Spectral Studies ◽  
Special Pair ◽  
Self Assembled ◽  
Alkyl Ammonium ◽  
Porphyrin Dimer

Using a self-assembled supramolecular approach, a closer model for the photosynthetic reaction center 'special pair' assembled with an electron acceptor conjugate, is reported. As the 'special pair' donor, magnesium meso-(benzo-15-crown-5)porphyrin was self-assembled with K + to form a highly stable Mg porphyrin dimer with a co-facial geometry arrangement, which is a better electron donor since it is nearly 130 mV easier to oxidize compared to the earlier reported Zn porphyrin dimer analog. Further, pyridine and alkyl ammonium cation-functionalized fullerene was attached via axial coordination and crown ether-alkyl ammonium cation complexation to form the four-fold, donor-acceptor complex. The self-assembled supramolecular complex, constructed using this approach, possesses defined geometry and orientation. Efficient charge separation from the singlet excited state of the Mg porphyrin dimer to the fullerene entity and a relatively slow charge recombination, were revealed by time-resolved emission and nanosecond transient absorption spectral studies, supporting the impending exploitation of these novel biomimetic model systems for light energy harvesting applications.

scholarly journals Electron tunneling pathway in photosynthetic reaction center changes with the fluctuation of protein environment

2003 ◽  
Vol 43 (supplement) ◽  
pp. S199
Author(s):  
H. Nishioka ◽  
T. Kawatsu ◽  
A. Kimura ◽  
T. Yamato ◽  
T. Kakitani
Keyword(s):  
Reaction Center ◽  
Electron Tunneling ◽  
Photosynthetic Reaction Center ◽  
Protein Environment
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