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Indian Journal of Biochemistry and Biophysics (IJBB) >
IJBB Vol.49 [2012] >
IJBB Vol.49(4) [August 2012] >
| Title: | A molecular model of artificial photosynthesis: Mn-Ca binuclear complex for photosynthetic oxidation of water |
| Authors: | Mishra, Nibedita
Mohapatra, Pranab Kishor
Raval, Mukesh Kumar
Biswal, Basanti
Biswal, Uday Chand |
| Keywords: | Molecular modeling
Photosynthetic water oxidation
Photosystem II
Quantum mechanical calculations
Oxygen evolving complex
Mn-Ca binuclear complex |
| Issue Date: | Aug-2012 |
| Publisher: | NISCAIR-CSIR, India |
| Abstract: | The redox active component of oxygenic
photosynthetic reaction center II contains metal cluster Mn4-Ca,
where two H2O are oxidized to O2 and four H+
ions are liberated. A binuclear Mn-Ca metal center binding one substrate H2O
on each ion is proposed to be the minimal unit of the redox center. A model for
the water oxidizing metal cluster is built with molecular modeling software
(HyperChem 8.0 Pro). Mn, being a transitional metal with variable valency is
redox active, while Ca is redox inert. Formation and deprotonation of H2O˙+
on MnIII may be favorable compared to Ca. Deprotonation of H2O˙+
yields a stable species HOˉ on MnIV by transfer of one electron from
MnIII as a consequence of first photoact. Similarly, during second
photoact, it may lead to formation of MnV = O. The O-O bond may be
formed in the third photoact between O on Mn and H2O on Ca.
Subsequently, HO2˙ˉ may be formed, leading to formation of O2.
Molecular models are built for each transition states. |
| Page(s): | 246-249 |
| CC License: |  CC Attribution-Noncommercial-No Derivative Works 2.5 India |
| ISSN: | 0975-0959 (Online); 0301-1208 (Print) |
| Source: | IJBB Vol.49(4) [August 2012]
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