Lateral mobility of the light-harvesting complex in chloroplast membranes controls excitation energy distribution in higher plants

D. J. Kyle, L. A. Staehelin, C. J. Arntzen

Research output: Contribution to journalArticlepeer-review

165 Scopus citations

Abstract

Chloroplast thylakoid protein phosphorylation produces changes in light-harvesting properties and in membrane structure as revealed by freeze-fracture electron microscopy. Protein phosphorylation resulted in an increase in the 77 °K fluorescence signal at 735 nm relative to that at 685 nm. In addition, a decrease in connectivity between Photosystem II centers (PS II) and a dynamic quenching of the room temperature variable fluorescence was observed upon phosphorylation. Accompanying these fluorescence changes was a 23% decrease in the amount of stacked membranes. Microscopic analyses indicated that 8.0-nm particles fracturing on the P-face moved from the stacked into the unstacked regions upon phosphorylation. The movement of the 8.0-nm particles was accompanied by the appearance of chlorophyll b and 25 to 29 kD polypeptides in isolated stroma lamellae fractions. We conclude that phosphorylation of a population of the light-harvesting chlorophyll a b protein complexes (LHC) in grana partitions causes the migration of these pigment proteins from the PS II-rich appressed membranes into the Photosystem I (PS I) enriched unstacked regions. This increases the absorptive cross section of PS I. In addition, we suggest that the mobile population of LHC functions to interconnect PS II centers in grana partitions; removal of this population of LHC upon phosphorylation limits PS II → PS II energy transfer and thereby favors spillover of energy from PS II to PS I.

Original languageEnglish (US)
Pages (from-to)527-541
Number of pages15
JournalArchives of Biochemistry and Biophysics
Volume222
Issue number2
DOIs
StatePublished - Apr 15 1983

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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