Effect of heptane-extraction on the stability of subunit organization of photosystem I reaction center complexes

Yuichiro Takahashi, Sakae Katoh

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Treatment of lyophilized thylakoid membranes of the thermophilic cyanobacterium Synechococcus sp. with n-heptane for 6 h resulted in marked changes in the pattern of photosystem I reaction center complexes resolved by sodium dodecylsulfate-polyacrylamide gel electrophoresis. CP1-a, which consists of two large subunits and three small subunits, was a major chlorophyll-containing band resolved from the lyophilized thylakoid membranes, whereas the heptane-extracted membranes produced mainly CP1-e which totally lacks the small subunits. Electron transport from the primary donor P700 to the secondary acceptor P430 was not affected by the heptane-extraction of the membranes. The heptane-treatment removed 97% of β-carotene present in the membranes, whereas all chlorophyll a, a major part of xanthophylls, more than a half of phylloquinone and one third of plastoquinone remained unextracted. The data suggest that β-carotene has an important structural effect to stabilize the subunit organization of photosystem I reaction center complexes but is not essential for the early photochemical events of photosystem I.

Original languageEnglish
Pages (from-to)29-36
Number of pages8
JournalPhotosynthesis Research
Issue number1
Publication statusPublished - Jan 1987
Externally publishedYes



  • β-carotene
  • (Synechococcus sp.)
  • heptane extraction
  • Photosystem I reaction center
  • phylloquinone (vitamin K)
  • subunit structure

ASJC Scopus subject areas

  • Plant Science

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