Origin of pronounced differences in 77 K fluorescence of the green alga Chlamydomonas reinhardtii in state 1 and 2

Caner Ünlü, Iryna Polukhina, Herbert van Amerongen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

In response to changes in the reduction state of the plastoquinone pool in its thylakoid membrane, the green alga Chlamydomonas reinhardtti is performing state transitions: remodelling of its thylakoid membrane leads to a redistribution of excitations over photosystems I and II (PSI and PSII). These transitions are accompanied by marked changes in the 77 K fluorescence spectrum, which form the accepted signature of state transitions. The changes are generally thought to reflect a redistribution of light-harvesting complexes (LHCs) over PSII (fluorescing below 700 nm) and PSI (fluorescing above 700 nm). Here we studied the picosecond fluorescence properties of C. reinhardtti over a broad range of wavelengths with very low excitation intensities (0.2 nJ per laser pulse). Cells were directly used for time-resolved fluorescence measurements at 77 K without further treatment, such as medium exchange with glycerol. It is observed that upon going from state 1 (relatively more fluorescence below 700 nm) to state 2 (relatively more fluorescence above 700 nm), a large part of the fluorescence of LHC/PSII becomes substantially quenched in concurrence with LHC detachment from PSII, whereas the absolute amount of PSI fluorescence hardly changes. These results are in agreement with the recent proposal that the amount of LHC moving from PSII to PSI upon going from state 1 to state 2 is rather limited (Unlu et al. Proc Natl Acad Sci USA 111 (9):3460–3465, 2014).

Original languageEnglish
Pages (from-to)209-217
Number of pages9
JournalEuropean Biophysics Journal
Volume45
Issue number3
DOIs
Publication statusPublished - 1 Apr 2016
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2015, European Biophysical Societies' Association.

Funding

This work was supported financially by The Netherlands Organization for Scientific Research (NWO) via the Council for Chemical Sciences (HvA) and also partly supported by the BioSolar Cells Programme of The Netherlands Ministry of Economic Affairs Agriculture and Innovation and by the Foundation for Fundamental Research on Matter (FOM).

FundersFunder number
BioSolar Cells Programme of The Netherlands Ministry of Economic Affairs Agriculture and Innovation
HvA
Stichting voor Fundamenteel Onderzoek der Materie
Nederlandse Organisatie voor Wetenschappelijk Onderzoek

    Keywords

    • Excitation energy transfer
    • Fluorescence quenching
    • Light harvesting
    • Photosystem
    • State transitions
    • Time-resolved fluorescence spectroscopy

    Fingerprint

    Dive into the research topics of 'Origin of pronounced differences in 77 K fluorescence of the green alga Chlamydomonas reinhardtii in state 1 and 2'. Together they form a unique fingerprint.

    Cite this