title: Photochemistry in the isolated Photosystem II reaction-centre core complex.
abstract: The photochemistry of the isolated Photosystem II reaction-centre core from pea and the green alga Scenedesmus was examined by e.s.r. Two types of triplet spectrum were observed in addition to the spin-polarized reaction-centre triplet previously identified. The additional triplet formed on continuous illumination at 4.2 K was attributed to a monomeric phaeophytin molecule. The second triplet, which was stable in the dark at 4.2 K following illumination, was assigned to the radical pair Donor+I-. This provides evidence that an electron donor to chlorophyll P680 is present on the polypeptide D1-polypeptide D2-cytochrome b-559 core complex.
authors.affiliation: Department of Biology, University College London, U.K.
authors.forename: C
authors.initials: C
authors.lastname: Demetriou
authors.forename: C J
authors.initials: CJ
authors.lastname: Lockett
authors.forename: J H
authors.initials: JH
authors.lastname: Nugent
mesh_terms: D002734:Chlorophyll; D000460:Chlorophyta / Q000032:analysis; D004578:Electron Spin Resonance Spectroscopy; D007887:Fabaceae / Q000032:analysis; D045342:Light-Harvesting Protein Complexes; D010777:Photochemistry; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D010946:Plants, Medicinal
chemical_list: D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D002734:Chlorophyll