The lifetimes and energies of the first excited singlet states of diadinoxanthin and diatoxanthin: The role of these molecules in excess energy dissipation in algae

Harry A. Frank, Agnes Cua, Veeradej Chynwat, Andrew Young, David Gosztola, Michael R. Wasielewski

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

The lifetimes of the first excited singlet states (21A(g)) of diadinoxanthin and diatoxanthin, carotenoids involved in the xanthophyll cycle in some genera of algae, have been measured by femtosecond time-resolved optical spectroscopy to be 22.8 ± 0.1 ps and 13.3 ± 0.1 ps, respectively. Using the energy gap law for radiationless transitions set forth by Englman and Jortner (Mol. Phys. 18 (1970) 145-164), these lifetimes correspond to S1 excited state energies of 15,210 cm-1 for diadinoxanthin and 14,620 cm-1 for diatoxanthin. The lowest excited singlet state energy of Chl a has an energy of 14,700 cm-1. The fact that the S1 state energy of diadinoxanthin lies above that of Chl a, whereas the S1 state energy of diatoxanthin lies below that of Chl a, suggests that the xanthophyll cycle involving the enzymatic interconversion of diadinoxanthin and diatoxanthin may play a role in regulating energy flow between these molecules and Chl a in many species of algae, essentially fulfilling a role identical to that proposed for violaxanthin and zeaxanthin in higher plants and green algae (Frank et al. (1994) Photosyn. Res. 41, 389-395).

Original languageEnglish
Pages (from-to)243-252
Number of pages10
JournalBiochimica et Biophysica Acta - Bioenergetics
Volume1277
Issue number3
DOIs
Publication statusPublished - Dec 18 1996

Keywords

  • Diadinoxanthin
  • Diatoxanthin
  • Energy dissipation
  • Excited state
  • Femtosecond
  • Optical spectroscopy
  • Xantophyll cycle

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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