title: Chlorophyll fluorescence quenching in isolated light harvesting complexes induced by zeaxanthin.
abstract: Non-photochemical quenching of chlorophyll fluorescence in plants occurs in the light harvesting antenna of photosystem II and is regulated by the xanthophyll cycle. A new in vitro model for this process has been developed. Purified light harvesting complexes above the detergent critical micelle concentration have a stable high fluorescence yield but a rapidly inducible fluorescence quenching occurs upon addition of zeaxanthin. Violaxanthin was without effect, lutein and antheraxanthin induced a marginal response, whereas the violaxanthin analogue, auroxanthin, induced strong quenching. Quenching was not caused by aggregation of the complexes but was accompanied by a spectral broadening and red shift, indicating a zeaxanthin-dependent alteration in the chlorophyll environment.
authors.affiliation: Robert Hill Institute for Photosynthesis Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield, UK.
authors.forename: M
authors.initials: M
authors.lastname: Wentworth
authors.forename: A V
authors.initials: AV
authors.lastname: Ruban
authors.forename: P
authors.initials: P
authors.lastname: Horton
mesh_terms: D002734:Chlorophyll / Q000737:chemistry* / Q000378:metabolism; D005453:Fluorescence; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins / Q000187:drug effects* / Q000378:metabolism; D045332:Photosystem II Protein Complex; D018724:Spinacia oleracea / Q000378:metabolism; D024341:Xanthophylls; D065146:Zeaxanthins; D019207:beta Carotene / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D024341:Xanthophylls; D065146:Zeaxanthins; D019207:beta Carotene; D002734:Chlorophyll; C005613:violaxanthin