Identification of proton-active residues in a higher plant light-harvesting complex.

ABSTRACT: The thermal dissipation of absorbed light energy by the light-harvesting apparatus of higher plants is important in protecting the photosynthetic machinery from the effects of excess illumination. A major mechanism for such photoprotection, known as trans-thylakoid delta pH-dependent chlorophyll fluorescence quenching (qE), is induced by acidification of the lumen, is correlated with the interconversion of xanthophyll pigments, and is manifested as quenching of chloropyll fluorescence. The mechanistic basis for qE remains unknown. The reagent N, N'-dicyclohexylcarbodiimide (DCCD) specifically inhibits qE and covalently binds to two minor light-harvesting pigment-protein complexes (LHCII), LHCIIa and LHCIIc. It is shown that DCCD treatment of isolated LHCIIc complexes reverses acid-induced

SUBMITTER: Walters RG 

PROVIDER: S-EPMC19518 | biostudies-literature | 1996 Nov

REPOSITORIES: biostudies-literature