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The light-harvesting antenna of the diatom Phaeodactylum tricornutum. Evidence for a diadinoxanthin-binding subcomplex.

Authors
  • Guglielmi, Gérard
  • Lavaud, Johann
  • Rousseau, Bernard
  • Etienne, Anne-Lise
  • Houmard, Jean
  • Ruban, Alexander V
Type
Published Article
Journal
FEBS Journal
Publisher
Wiley (Blackwell Publishing)
Publication Date
August 2005
Volume
272
Issue
17
Pages
4339–4348
Identifiers
PMID: 16128804
Source
Medline
License
Unknown

Abstract

Diatoms differ from higher plants by their antenna system, in terms of both polypeptide and pigment contents. A rapid isolation procedure was designed for the membrane-intrinsic light harvesting complexes (LHC) of the diatom Phaeodactylum tricornutum to establish whether different LHC subcomplexes exist, as well to determine an uneven distribution between them of pigments and polypeptides. Two distinct fractions were separated that contain functional oligomeric complexes. The major and more stable complex ( approximately 75% of total polypeptides) carries most of the chlorophyll a, and almost only one type of carotenoid, fucoxanthin. The minor complex, carrying approximately 10-15% of the total antenna chlorophyll and only a little chlorophyll c, is highly enriched in diadinoxanthin, the main xanthophyll cycle carotenoid. The two complexes also differ in their polypeptide composition, suggesting specialized functions within the antenna. The diadinoxanthin-enriched complex could be where the de-epoxidation of diadinoxanthin into diatoxanthin mostly occurs.

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