Pigment Stoichiometry of the Photosystem II Reaction Center from Higher Plants

María Aured, Esmeralda Moliner, Miguel Alfonso, Inmaculada Yruela, Stephen P. Toon, Michael Seibert, Rafael Picorel

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9 Scopus Citations


A preparation of Photosystem II reaction center complex containing 4 chlorophylls per 2 pheophytins was obtained from three different species of higher plants. A 'standard' reaction center preparation (6 Chl/2 Pheo) was used as starting material. This material was loaded onto a sieve chromatography Superose-6 column run on a FPLC system. Three different sets of fractions were eluted from the column. The first few fractions showed a distinct absorption band at 435 nm and pigment content of 10 Chl per 2 Pheo. The peak fractions did not show a distinct band at 435 nm, but rather a shoulder, and contained 4 Chl per 2 Pheo. The few last fractions exhibited relatively higher absorption at 416 nm, most probably due to higher cytochrome content, but they also contained 4 Chl per 2 Pheo. Similar results were observed when a reaction center preparation of about 5 Chl was loaded onto the Superose-6 column. This indicates that the 'standard' Photosystem II reaction center preparation is heterogenous, composed of 4 Chl reaction centers and contaminants containing higher pigment content. To further validate this conclusion, we obtained a 4 Chl preparation by modification of the 'standard' reaction center purification procedure. After loading this preparation onto the Superose-6 column, one single chromatographic band was obtained, and all fractions contained 4 Chl per 2 Pheo. This strongly suggests that a 4 Chl per 2 Pheo preparation corresponds to that of a native core Photosystem II reaction center preparation.

Original languageAmerican English
Pages (from-to)187-190
Number of pages4
JournalBBA - Bioenergetics
Issue number2
StatePublished - 1994

NREL Publication Number

  • NREL/JA-452-6615


  • Chlorophyll
  • Chromatography
  • FPLC
  • Pheophytin
  • Photosynthesis
  • Pigment stoichiometry
  • Reaction center


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