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Title: Macroorganization of Chlorophyll a/b light-harvesting complex in thylakoids and aggregates: information from circular differential scattering

Abstract

Circular dichroism (CD) and magnetic circular dichroism (MCD) spectra were recorded for spinach thylakoids and for isolated, aggregated chlorophyll a/b light-harvesting pigment-protein complex, in random and magnetically aligned states of orientation at room and low temperatures. The shape and magnitude of the CD signal of most bands strongly depended on the orientation of the thylakoid membranes or the aggregated pigment-protein complex. In both thylakoids and aggregated light-harvesting complexes, however, the MCD spectra of the two different orientations were almost identical. Random and magnetically aligned samples exhibited anomalous, large CD signals outside the bands of pigment absorbance. Lack of similarity between the corresponding MCD and CD spectra showed that the large CD signals are not produced as a distortion of CD of absorbance by light scattering. Instead, these anomalous spectral features are believed to originate in differential selective scattering of circularly polarized light. The results lead to the conclusion that the light-harvesting pigment-protein complex in thylakoid grana forms a helical macroarray with dimensions commensurate with the wavelengths of the anomalous circular dichroism signals. A hypothesis is put forward suggesting a role for these macrodomains in granal organization.

Authors:
; ; ;
Publication Date:
Research Org.:
Brookhaven National Lab., Upton, NY (USA)
OSTI Identifier:
5199566
Resource Type:
Journal Article
Journal Name:
Biochemistry; (United States)
Additional Journal Information:
Journal Volume: 27:7
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; CHLOROPHYLL; MAGNETIC CIRCULAR DICHROISM; CHLOROPHYLL-BINDING PROTEINS; ABSORPTION SPECTRA; CHLOROPLASTS; SPINACH; CARBOXYLIC ACIDS; CELL CONSTITUENTS; DICHROISM; FOOD; HETEROCYCLIC ACIDS; HETEROCYCLIC COMPOUNDS; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; PHOTOSYNTHETIC REACTION CENTERS; PHYTOCHROMES; PIGMENTS; PLANTS; PORPHYRINS; PROTEINS; SPECTRA; VEGETABLES; 140505* - Solar Energy Conversion- Photochemical, Photobiological, & Thermochemical Conversion- (1980-)

Citation Formats

Garab, G, Faludi-Daniel, A, Sutherland, J C, and Hind, G. Macroorganization of Chlorophyll a/b light-harvesting complex in thylakoids and aggregates: information from circular differential scattering. United States: N. p., 1988. Web. doi:10.1021/bi00407a027.
Garab, G, Faludi-Daniel, A, Sutherland, J C, & Hind, G. Macroorganization of Chlorophyll a/b light-harvesting complex in thylakoids and aggregates: information from circular differential scattering. United States. doi:10.1021/bi00407a027.
Garab, G, Faludi-Daniel, A, Sutherland, J C, and Hind, G. Tue . "Macroorganization of Chlorophyll a/b light-harvesting complex in thylakoids and aggregates: information from circular differential scattering". United States. doi:10.1021/bi00407a027.
@article{osti_5199566,
title = {Macroorganization of Chlorophyll a/b light-harvesting complex in thylakoids and aggregates: information from circular differential scattering},
author = {Garab, G and Faludi-Daniel, A and Sutherland, J C and Hind, G},
abstractNote = {Circular dichroism (CD) and magnetic circular dichroism (MCD) spectra were recorded for spinach thylakoids and for isolated, aggregated chlorophyll a/b light-harvesting pigment-protein complex, in random and magnetically aligned states of orientation at room and low temperatures. The shape and magnitude of the CD signal of most bands strongly depended on the orientation of the thylakoid membranes or the aggregated pigment-protein complex. In both thylakoids and aggregated light-harvesting complexes, however, the MCD spectra of the two different orientations were almost identical. Random and magnetically aligned samples exhibited anomalous, large CD signals outside the bands of pigment absorbance. Lack of similarity between the corresponding MCD and CD spectra showed that the large CD signals are not produced as a distortion of CD of absorbance by light scattering. Instead, these anomalous spectral features are believed to originate in differential selective scattering of circularly polarized light. The results lead to the conclusion that the light-harvesting pigment-protein complex in thylakoid grana forms a helical macroarray with dimensions commensurate with the wavelengths of the anomalous circular dichroism signals. A hypothesis is put forward suggesting a role for these macrodomains in granal organization.},
doi = {10.1021/bi00407a027},
journal = {Biochemistry; (United States)},
number = ,
volume = 27:7,
place = {United States},
year = {1988},
month = {4}
}