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Excitation energy trapping by the reaction center of Rhodobacter Sphaeroides
Author(s) -
Damjanović Ana,
Ritz Thorsten,
Schulten Klaus
Publication year - 2000
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(2000)77:1<139::aid-qua13>3.0.co;2-s
Subject(s) - rhodobacter sphaeroides , bacteriochlorophyll , photosynthetic reaction centre , excitation , delocalized electron , chemistry , atomic physics , excited state , hamiltonian (control theory) , quantum , molecular physics , physics , electron transfer , photochemistry , quantum mechanics , photosynthesis , mathematical optimization , biochemistry , mathematics , organic chemistry
The excitation energy transfer between light‐harvesting complex I (LH‐I) and the photosynthetic reaction center (RC) of the purple bacterium Rhodobacter (Rb.) sphaeroides is investigated on the basis of the atomic level structures of the two proteins, assuming a ring‐shaped model for LH‐I. Rates of excitation energy transfer are calculated, based on Förster theory. The LH‐I and RC electronic excitations are described through effective Hamiltonians established previously, with parameters derived from quantum chemistry calculations by Cory and co‐workers. We also present an effective Hamiltonian description with parameters based on spectroscopic properties. We study two extreme models of LH‐I excitations: electronic excitations delocalized over the entire LH‐I ring and excitations localized on single bacteriochlorophylls. The role of accessory bacteriochlorophylls in bridging the excitation energy transfer is investigated. The rates of back‐transfer, i.e., RC → LH‐I excitation energy transfer, are determined, too. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 77: 139–151, 2000