title: A well resolved ODMR triplet minus singlet spectrum of P680 from PSII particles.
abstract: An ADMR T-S spectrum of the primary donor (P680) of photosystem II (PSII) was obtained from anaerobically photoreduced particles. The spectrum is the best resolved obtained so far having a main bleaching band at 684 nm with a linewidth of only 100 cm-1. The view that this spectrum is produced by native homogeneous P680 unlike those obtained before is defended. A small bleaching observed at 678 nm is discussed in terms of the reaction center structure. One possible interpretation of the observations is that P680 is a very loose dimer with an exciton splitting of only 144 cm-1 corresponding to a dimer center-to-center distance of roughly 11.5 A.
authors.affiliation: Department of Physical Chemistry, University of Padua, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Carbonera
authors.forename: G
authors.initials: G
authors.lastname: Giacometti
authors.forename: G
authors.initials: G
authors.lastname: Agostini
mesh_terms: D002734:Chlorophyll / Q000737:chemistry*; D045342:Light-Harvesting Protein Complexes; D009682:Magnetic Resonance Spectroscopy; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D045332:Photosystem II Protein Complex; D014675:Vegetables / Q000737:chemistry
chemical_list: D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D002734:Chlorophyll; C025167:P-680