Photosynthesis Research

, Volume 86, Issue 1, pp 283–296

A Fluorescence Detected Magnetic Resonance Investigation of the Carotenoid Triplet States Associated with Photosystem II of Isolated Spinach Thylakoid Membranes

  • Stefano Santabarbara
  • Giancarlo Agostini
  • Peter Heathcote
  • Donatella Carbonera
Regular Paper

DOI: 10.1007/s11120-005-2840-1

Cite this article as:
Santabarbara, S., Agostini, G., Heathcote, P. et al. Photosynth Res (2005) 86: 283. doi:10.1007/s11120-005-2840-1

Abstract

The carotenoid triplet populations associated with the fluorescence emission chlorophyll forms of Photosystem II have been investigated in isolated spinach thylakoid membranes by means of fluorescence detected magnetic resonance in zero field (FDMR). The spectra collected in the 680–690 nm emission range, have been fitted by a global analysis procedure. At least five different carotenoid triplet states coupled to the terminal emitting chlorophyll forms of PS II, peaking at 682 nm, 687 nm and 692 nm, have been characterised. The triplets associated with the outer antenna emission forms, at 682 nm, have zero field splitting parameters |D| = 0.0385 cm−1, |E| = 0.00367 cm−1; |D| = 0.0404 cm−1, |E| = 0.00379 cm−1 and |D| = 0.0386 cm−1, |E| = 0.00406 cm−1 which are very similar to those previously reported for the xanthophylls of the isolated LHC II complex. Therefore the FDMR spectra recorded in this work provide insights into the organisation of the LHC II complex in the unperturbed environment represented by thylakoid membranes. The additional carotenoid triplet populations, detected by monitoring the chlorophyll emission at 687 and 692 nm, are assigned to carotenoids bound to inner antenna complexes and hence attributed to β-carotene molecules.

Keywords

carotenoid light harvesting complexes ODMR Photosystem II triplet states 

Abbreviations

ADMR

absorbance detected magnetic resonance

Car

carotenoid

Chl

chlorophyll

FDMR

fluorescence detected magnetic resonance

MIF

microwave induced fluorescence

ODMR

optically detected magnetic resonance

PS I

Photosystem I

PS II

Photosystem II

ZFS

zero field splitting

Copyright information

© Springer 2005

Authors and Affiliations

  • Stefano Santabarbara
    • 1
  • Giancarlo Agostini
    • 2
  • Peter Heathcote
    • 1
  • Donatella Carbonera
    • 3
  1. 1.School of Biological SciencesQueen Mary University of LondonLondonUK
  2. 2.Consiglio Nazionale delle Ricerche,Istituto di Chimica BiomolecolareSezione di PadovaPadovaItaly
  3. 3.Dipartimento di Scienze ChimicheUniversità di PadovaPadovaItaly