title: Polyamines induce aggregation of LHC II and quenching of fluorescence in vitro.
abstract: Dissipation of excess excitation energy within the light-harvesting complex of Photosystem II (LHC II) is a main process in plants, which is measured as the non-photochemical quenching of chlorophyll fluorescence or qE. We showed in previous works that polyamines stimulate qE in higher plants in vivo and in eukaryotic algae in vitro. In the present contribution we have tested whether polyamines can stimulate quenching in trimeric LHC II and monomeric light-harvesting complex b proteins from higher plants. The tetramine spermine was the most potent quencher and induced aggregation of LHC II trimers, due to its highly cationic character. Two transients are evident at 100 μM and 350 μM for the fluorescence and absorbance signals of LHC II respectively. On the basis of observations within this work, some links between polyamines and the activation of qE in vivo is discussed.
authors.affiliation: Department of Biology, University of Crete, P.O. Box 2208, GR-71409 Heraklion, Crete, Greece.
authors.forename: Theodoros
authors.initials: T
authors.lastname: Tsiavos
authors.forename: Nikolaos E
authors.initials: NE
authors.lastname: Ioannidis
authors.forename: Kiriakos
authors.initials: K
authors.lastname: Kotzabasis
mesh_terms: D000042:Absorption; D002338:Carotenoids / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D002734:Chlorophyll / Q000378:metabolism; D005453:Fluorescence; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000302:isolation & purification; D008958:Models, Molecular; D018532:Pisum sativum / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000302:isolation & purification; D011073:Polyamines / Q000494:pharmacology*; D055503:Protein Multimerization / Q000187:drug effects; D012995:Solubility; D013059:Spectrum Analysis, Raman; D018724:Spinacia oleracea / Q000378:metabolism; D020524:Thylakoids / Q000187:drug effects / Q000378:metabolism
chemical_list: D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex; D011073:Polyamines; D002734:Chlorophyll; D002338:Carotenoids