Electron-transfer pathways in the primary event of bacterial photosynthesis

Journal Article · Thu May 05 00:00:00 EDT 1988 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100320a057· OSTI ID:7143476

Warshel, A; Creighton, S; Parson, W W

The photochemical reaction in bacterial photosynthesis is the transfer of an electron from a bacteriochlorophyll dimer (P) to a bacteriopheophytin (H), possibly by way of another bacteriochlorophyll (B). The authors explore the mechanism of this reaction by calculating quantum-mechanical matrix elements for the electronic coupling of the exciton states and intermolecular charge-transfer (CT) states of the photosynthetic reaction center. The calculations are based on the crystal structure of the Rhodopseudomonas viridis reaction center and on semiempirical atomic resonance integrals. Five possible mechanisms for charge separation are considered. The matrix elements for a pathway via the intermediate CT state P/sup +/B/sup -/ are consistent with the experimentally measured kinetics of the reaction, but this pathway requires a remarkable stabilization of the CT state by the protein. An alternative pathway via B/sup +/H/sup -/ could be more favorable energetically, but has somewhat smaller coupling elements.

• Research Organization: Univ. of Southern California, Los Angeles (USA)
• OSTI ID: 7143476
• Journal Information: J. Phys. Chem.; (United States), Vol. 92:9
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
14 SOLAR ENERGY
PHOTOSYNTHESIS
ELECTRON TRANSFER
CHEMICAL REACTION KINETICS
DIABATIC APPROXIMATION
DIMERS
ELECTRONIC STRUCTURE
EXPERIMENTAL DATA
HAMILTONIANS
MATHEMATICAL MODELS
MATRIX ELEMENTS
PHOTOSYNTHETIC BACTERIA
THEORETICAL DATA
WAVE FUNCTIONS
CHEMICAL REACTIONS
DATA
FUNCTIONS
INFORMATION
KINETICS
MATHEMATICAL OPERATORS
NUMERICAL DATA
PHOTOCHEMICAL REACTIONS
QUANTUM OPERATORS
REACTION KINETICS
SYNTHESIS
400500* - Photochemistry
140505 - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)