title: Origin of the F685 and F695 fluorescence in photosystem II.
abstract: The emission spectra of CP47-RC and core complexes of Photosystem II (PS II) were measured at different temperatures and excitation wavelengths in order to establish the origin of the emission and the role of the core antenna in the energy transfer and charge separation processes in PS II. Both types of particles reveal strong dependences of spectral shape and yield on temperature. The results indicate that the well-known F-695 emission at 77 K arises from excitations that are trapped on a red-absorbing CP47 chlorophyll, whereas the F-685 nm emission at 77 K arises from excitations that are transferred slowly from 683 nm states in CP47 and CP43 to the RC, where they are trapped by charge separation. We conclude that F-695 at 77 K originates from the low-energy part of the inhomogeneous distribution of the 690 nm absorbing chlorophyll of CP47, while at 4 K the fluorescence originates from the complete distribution of the 690 nm chlorophyll of CP47 and from the low-energy part of the inhomogeneous distribution of one or more CP43 chlorophylls.
authors.affiliation: Faculty of Sciences, Division of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands. elena@nat.vu.nl
authors.forename: Elena G
authors.initials: EG
authors.lastname: Andrizhiyevskaya
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Chojnicka
authors.forename: James A
authors.initials: JA
authors.lastname: Bautista
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Diner
authors.forename: Rienk
authors.initials: R
authors.lastname: van Grondelle
authors.forename: Jan P
authors.initials: JP
authors.lastname: Dekker
mesh_terms: D004579:Electron Transport; D004735:Energy Transfer; D005453:Fluorescence; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000378:metabolism*; D018724:Spinacia oleracea / Q000737:chemistry / Q000378:metabolism*; D046939:Synechocystis / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature
chemical_list: D045332:Photosystem II Protein Complex