title: Violaxanthin inhibits nonphotochemical quenching in light-harvesting antenna of Chromera velia.
abstract: Non-photochemical quenching (NPQ) is a photoprotective mechanism in light-harvesting antennae. NPQ is triggered by chloroplast thylakoid lumen acidification and is accompanied by violaxanthin de-epoxidation to zeaxanthin, which further stimulates NPQ. In the present study, we show that violaxanthin can act in the opposite direction to zeaxanthin because an increase in the concentration of violaxanthin reduced NPQ in the light-harvesting antennae of Chromera velia. The correlation overlapped with a similar relationship between violaxanthin and NPQ as observed in isolated higher plant light-harvesting complex II. The data suggest that violaxanthin in C. velia can act as an inhibitor of NPQ, indicating that violaxanthin has to be removed from the vicinity of the protein to reach maximal NPQ.
authors.affiliation: Institute of Microbiology, Academy of Sciences of the Czech Republic, Třeboň, Czech Republic.|Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic.
authors.forename: Radek
authors.initials: R
authors.lastname: Kaňa
authors.affiliation: Institute of Microbiology, Academy of Sciences of the Czech Republic, Třeboň, Czech Republic.|Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic.
authors.forename: Eva
authors.initials: E
authors.lastname: Kotabová
authors.affiliation: Institute of Microbiology, Academy of Sciences of the Czech Republic, Třeboň, Czech Republic.
authors.forename: Jana
authors.initials: J
authors.lastname: Kopečná
authors.affiliation: Institute of Microbiology, Academy of Sciences of the Czech Republic, Třeboň, Czech Republic.|Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic.
authors.forename: Eliška
authors.initials: E
authors.lastname: Trsková
authors.affiliation: Institute of Microbiology, Academy of Sciences of the Czech Republic, Třeboň, Czech Republic.|School of Biological and Chemical Sciences, Queen Mary University of London, UK.
authors.forename: Erica
authors.initials: E
authors.lastname: Belgio
authors.affiliation: Institute of Microbiology, Academy of Sciences of the Czech Republic, Třeboň, Czech Republic.|Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic.
authors.forename: Roman
authors.initials: R
authors.lastname: Sobotka
authors.affiliation: School of Biological and Chemical Sciences, Queen Mary University of London, UK.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Ruban
mesh_terms: D056893:Alveolata / Q000166:cytology / Q000378:metabolism* / Q000528:radiation effects; D002734:Chlorophyll / Q000378:metabolism; D005453:Fluorescence; D045342:Light-Harvesting Protein Complexes / Q000302:isolation & purification / Q000378:metabolism*; D055668:Photochemical Processes; D013997:Time Factors; D024341:Xanthophylls / Q000378:metabolism
chemical_list: D045342:Light-Harvesting Protein Complexes; D024341:Xanthophylls; D002734:Chlorophyll; C005613:violaxanthin
keywords: Chromera velia; light-harvesting antennae; nonphotochemical quenching; photoprotection; violaxanthin; zeaxanthin