Two equilibration pools of chlorophylls in the Photosystem I core antenna of Chlamydomonas reinhardtii

Krzysztof Gibasiewicz, V. M. Ramesh, Su Lin, Kevin Redding, Neal Woodbury, Andrew Webber

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Femtosecond transient absorption spectroscopy was applied for a comparative study of excitation decay in several different Photosystem I (PSI) core preparations from the green alga Chlamydomonas reinhardtii. For PSI cores with a fully interconnected network of chlorophylls, the excitation energy was equilibrated over a pool of chlorophylls absorbing at ∼683 nm, independent of excitation wavelength [Gibasiewicz et al. J Phys Chem B 105:11498-11506, 2001; J Phys Chem B 106:6322-6330, 2002]. In preparations with impaired connectivity between chlorophylls, we have found that the spectrum of chlorophylls connected to the reaction center (i.e., with ∼20 ps decay time) over which the excitation is equilibrated becomes excitation-wavelength- dependent. Excitation at 670 nm is finally equilibrated over chlorophylls absorbing at ∼675 nm, whereas excitation at 695 nm or 700 nm is equilibrated over chlorophylls absorbing at ∼683 nm. This indicates that in the vicinity of the reaction center there are two spectrally different and spatially separated pools of chlorophylls that are equally capable of effective excitation energy transfer to the reaction center. We propose that they are related to the two groups of central PSI core chlorophylls lying on the opposite sides of reaction center.

Original languageEnglish (US)
Pages (from-to)55-63
Number of pages9
JournalPhotosynthesis Research
Volume92
Issue number1
DOIs
StatePublished - Apr 2007

Fingerprint

Photosystem I Protein Complex
Chlamydomonas reinhardtii
photosystem I
Chlorophyll
antennae
Antennas
chlorophyll
Excitation energy
wavelengths
deterioration
Wavelength
Chlorophyta
Energy Transfer
Algae
energy transfer
Absorption spectroscopy
Energy transfer
spectroscopy
Spectrum Analysis
energy

Keywords

  • Antenna
  • Chlorophylls
  • Excitation energy transfer
  • Femtosecond transient absorption
  • Photosystem I
  • Primary charge separation
  • Reaction center

ASJC Scopus subject areas

  • Plant Science

Cite this

Two equilibration pools of chlorophylls in the Photosystem I core antenna of Chlamydomonas reinhardtii. / Gibasiewicz, Krzysztof; Ramesh, V. M.; Lin, Su; Redding, Kevin; Woodbury, Neal; Webber, Andrew.

In: Photosynthesis Research, Vol. 92, No. 1, 04.2007, p. 55-63.

Research output: Contribution to journalArticle

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AU - Woodbury, Neal

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