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Theoretical determination of absolute free energy of reduction of plastoquinone-9 in photosystem II and of plastoquinone-n in DMF

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Title Theoretical determination of absolute free energy of reduction of plastoquinone-9 in photosystem II and of plastoquinone-n in DMF
 
Creator MEHTA, N
DATTA, SN
 
Subject poisson-boltzmann equation
photosynthetic reaction centers
quantum-chemical calculation
isoprenoid side-chain
binding free-energies
solvation free-energy
blue copper proteins
electron-transfer
redox potentials
conformational flexibility
static continuum electrostatics
multi-conformation continuum electrostatics
poisson-boltzmann
absolute free energy of reduction
 
Description We employed static continuum electrostatics and multi-conformation continuum electrostatics (MCCE) methods to determine the reduction potential (E(red)(0)) Of PQ-9 in a section of Photosystem 11 (PSII). Both methods relied on the finite difference Poisson-Boltzmann (FDPB) solution. The static method brings out a E(red)(0) value (0.01 V) that is close to the experimental one (0.05 V), thereby demonstrating that the surrounding environment critically decides the net free energy change. The E(red)(0) value obtained from MCCE (0.04 V) is even closer to the observed value, thereby indicating the importance of protein side-chain and proton motions in the electron transfer process. Furthermore, density functional theory-dielectric polarisable continuum model (DFT-DPCM) was employed to calculate the absolute free energy of reduction of plastoquinone-n (PQ-n, where n is the number of isoprenoid units) in N,N dimethyl formamide (DMF) solvent. The DFT-DPCM method produced reduction potential values of -0.59 and -0.65 V for PQ-1 and PQ-9, respectively. These are more or less in agreement with the experimentally reported values of -0.64 and -0.62 V, respectively. (C) 2008
 
Publisher ELSEVIER SCIENCE BV
 
Date 2011-07-27T02:48:56Z
2011-12-26T12:53:12Z
2011-12-27T05:40:25Z
2011-07-27T02:48:56Z
2011-12-26T12:53:12Z
2011-12-27T05:40:25Z
2008
 
Type Article
 
Identifier JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM, 870(40603), 15-22
0166-1280
http://dx.doi.org/10.1016/j.theochem.2008.08.031
http://dspace.library.iitb.ac.in/xmlui/handle/10054/7089
http://hdl.handle.net/10054/7089
 
Language en