Photosynthesis Research

, Volume 10, Issue 3, pp 217–222 | Cite as

The light-harvesting chlorophyll a/b protein acts as a torque aligning chloroplasts in a magnetic field

  • J. G. Kiss
  • Gy. I. Garab
  • Zs. M. Tóth
  • Á. Faludi-Dániel
I. Photosynthetic Unit; the Antenna System; and the Photosynthetic Pigments


Displacement of particles from the purified light-harvesting chlorophyll a/b protein aggregate (LHC) was studied in magnetic fields of various strengths (0 to 1.6 T) by polarized fluorescence measurements. Macromolecular aggregates of LHC have a considerable magnetic susceptibility which enables the particles to rotate and align with their nematic axes parallel with H. As LHC is embedded in a transmembrane direction thylakoids should align perpendicular to H, the mode of alignment experimentally observed in thylakoids. The value of the magnetic susceptibility could be estimated by relating it to the integral susceptibility of the chlorophyll molecules in LHC. The fitting of this value with the field strength dependency of the fluorescence polarization ratio (FP) revealed a relationship between the LHC content of various photosynthetic membranes and their capacity for alignment, which suggested that LHC might be the torque ordering chloroplasts in a magnetic field.

Key words

light-harvesting chlorophyll a/b protein liquid crystal magnetic susceptibility polarized fluorescence 



light-harvesting chlorophyll a/b protein


fluorescence polarization ratio, Iz/Iy


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Copyright information

© Martinus Nijhoff Publishers 1986

Authors and Affiliations

  • J. G. Kiss
    • 1
  • Gy. I. Garab
    • 1
  • Zs. M. Tóth
    • 1
  • Á. Faludi-Dániel
    • 1
  1. 1.Department of Plant Physiology, Biological Research CenterHungarian Academy of SciencesSzegedHungary

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