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Donatas Zigmantas. Portrait.

Donatas Zigmantas

Professor

Donatas Zigmantas. Portrait.

Zeaxanthin radical cation formation in minor light-harvesting complexes of higher plant antenna

Author

  • T. J. Avenson
  • T. K. Ahn
  • Donatas Zigmantas
  • K. K. Niyogi
  • Z. Li
  • M. Ballottari
  • R. Bassi
  • G. R. Fleming

Summary, in English

Previous work on intact thylakoid membranes showed that transient formation of a zeaxanthin radical cation was correlated with regulation of photosynthetic light-harvesting via energy-dependent quenching. A molecular mechanism for such quenching was proposed to involve charge transfer within a chlorophyll-zeaxanthin heterodimer. Using near infrared (880 - 1100 nm) transient absorption spectroscopy, we demonstrate that carotenoid (mainly zeaxanthin) radical cation generation occurs solely in isolated minor light-harvesting complexes that bind zeaxanthin, consistent with the engagement of charge transfer quenching therein. We estimated that less than 0.5% of the isolated minor complexes undergo charge transfer quenching in vitro, whereas the fraction of minor complexes estimated to be engaged in charge transfer quenching in isolated thylakoids was more than 80 times higher. We conclude that minor complexes which bind zeaxanthin are sites of charge transfer quenching in vivo and that they can assume Non-quenching and Quenching conformations, the equilibrium LHC(N) reversible arrow LHC(Q) of which is modulated by the transthylakoid pH gradient, the PsbS protein, and protein-protein interactions.

Publishing year

2008

Language

English

Pages

3550-3558

Publication/Series

Journal of Biological Chemistry

Volume

283

Issue

6

Document type

Journal article

Publisher

American Society for Biochemistry and Molecular Biology

Topic

  • Atom and Molecular Physics and Optics

Keywords

  • xanthophyll cycle
  • chlorophyll fluorescence
  • resolved fluorescence analysis
  • photosystem-ii
  • energy-dissipation
  • excited-states
  • in-vivo
  • protein cp26
  • oxygenic photosynthesis
  • green plants

Status

Published

ISBN/ISSN/Other

  • ISSN: 1083-351X