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Chlorophyll dichroism of three‐dimensional crystals of the light‐harvesting chlorophyll a / b ‐protein complex
Author(s) -
Kühlbrandt W.,
Becker A.,
Mäntele W.
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)81438-8
Subject(s) - linear dichroism , crystal (programming language) , crystallography , dichroism , circular dichroism , isotropy , anisotropy , chemistry , materials science , optics , physics , computer science , programming language
Thin three‐dimensional crystals of the light‐harvesting chlorophyll a / b ‐protein complex from pea chloroplast membranes were investigated by microspectrophotometry. Measurements of tilted crystals revealed pronounced linear dichroism in a direction perpendicular to the crystal plane but no observable dichroism in the crystal plane. Q y transition moments of chlorophylls were rotationally isotropic with respect to the crystal plane and partially aligned in this plane. Q x transition moments showed no preferential orientation and appeared to be wholly isotropic. The orientation of transition moments in the crystal was consistent with three‐fold symmetry of the light‐harvesting complex indicated by the crystal structure. The linear dichroism of the crystals reflected the optical properties of the complex in the photosynthetic membrane, indicating a highly symmetrical arrangement of antenna chlorophylls.