Orientation of pigments in the thylakoid membrane and in the isolated chlorophyll-protein complexes of higher plants. II. Linear dichroism spectra of isolated pigment-protein complexes oriented in polyacrylamide gels at 300 and 100 K

Philip Haworth, Pierre Tapie, Charles J. Arntzen, Jacques Breton

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Abstract

The absorption and linear dichroism (LD) spectra (380-780 nm) of isolated light-harvesting complex (LHC), Photosystem I (PS I), Photosystem II (PS II), as well as intact thylakoids have been determined at 300 and 100 K. The samples were oriented in squeezed polyacrylamide gel. The low-temperature spectra of LHC and PS I present LD signals which are characteristic enough to be recognized in the LD spectrum of thylakoids. Tentative assignments of the various features of the LD spectra to the major photosynthetic pigments are discussed. A shoulder in the low-temperature absorption spectra is observed at about 673 nm in all the systems under investigation. The absence of an associated LD signal suggests that this ubiquitous chlorophyll (Chl) a form is non-dichroic. Furthermore, in the three isolated chlorophyll-protein complexes described in this study the sign of the LD signal indicates that both the Qy transition of the Chl a and the carotenoid molecules are preferentially oriented parallel to the largest dimension(s) of the particles.

Original languageEnglish (US)
Pages (from-to)152-159
Number of pages8
JournalBBA - Bioenergetics
Volume682
Issue number1
DOIs
StatePublished - Oct 18 1982

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Keywords

  • (Pea chloroplast)
  • Chlorophyll-protein complex
  • Linear dichroism
  • Low temperature
  • Pigment orientation
  • Thylakoid membrane

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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