title: Fragment molecular orbital study of the electronic excitations in the photosynthetic reaction center of Blastochloris viridis.
abstract: All electron calculations were performed on the photosynthetic reaction center of Blastochloris viridis, using the fragment molecular orbital (FMO) method. The protein complex of 20,581 atoms and 77,754 electrons was divided into 1398 fragments, and the two-body expansion of FMO/6-31G* was applied to calculate the ground state. The excited electronic states of the embedded electron transfer system were separately calculated by the configuration interaction singles approach with the multilayer FMO method. Despite the structural symmetry of the system, asymmetric excitation energies were observed, especially on the bacteriopheophytin molecules. The asymmetry was attributed to electrostatic interaction with the surrounding proteins, in which the cytoplasmic side plays a major role.
authors.affiliation: Information Technology Research Institute, AIST, 1-1-1 Umezono, Tsukuba 305-8568, Japan. ikegam@ni.aist.go.jp
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Ikegami
authors.forename: Toyokazu
authors.initials: T
authors.lastname: Ishida
authors.forename: Dmitri G
authors.initials: DG
authors.lastname: Fedorov
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kitaura
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Inadomi
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Umeda
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Yokokawa
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sekiguchi
mesh_terms: D000465:Algorithms; D003593:Cytoplasm / Q000737:chemistry / Q000378:metabolism; D004579:Electron Transport; D004583:Electrons; D041921:Hyphomicrobiaceae / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D010674:Pheophytins / Q000737:chemistry* / Q000378:metabolism; D010788:Photosynthesis; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry* / Q000378:metabolism*; D011789:Quantum Theory; D055672:Static Electricity; D013816:Thermodynamics
chemical_list: D010674:Pheophytins; D045322:Photosynthetic Reaction Center Complex Proteins; C006678:bacteriopheophytin