Macroorganization of chlorophyll a/b light-harvesting complex in thylakoids and aggregates

Information from circular differential scattering

G. Garab, Agnes Faludi-Daniel, John C. Sutherland, Geoffrey Hind

Research output: Contribution to journalArticle

67 Citations (Scopus)

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. Our 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.

Original languageEnglish
Pages (from-to)2425-2430
Number of pages6
JournalBiochemistry
Volume27
Issue number7
Publication statusPublished - 1988

Fingerprint

Thylakoids
Circular Dichroism
Pigments
Scattering
Light
Light-Harvesting Protein Complexes
Proteins
Light polarization
Light scattering
Membranes
Wavelength
chlorophyll b
chlorophyll a
Spinacia oleracea
Temperature

ASJC Scopus subject areas

  • Biochemistry

Cite this

Macroorganization of chlorophyll a/b light-harvesting complex in thylakoids and aggregates : Information from circular differential scattering. / Garab, G.; Faludi-Daniel, Agnes; Sutherland, John C.; Hind, Geoffrey.

In: Biochemistry, Vol. 27, No. 7, 1988, p. 2425-2430.

Research output: Contribution to journalArticle

Garab, G. ; Faludi-Daniel, Agnes ; Sutherland, John C. ; Hind, Geoffrey. / Macroorganization of chlorophyll a/b light-harvesting complex in thylakoids and aggregates : Information from circular differential scattering. In: Biochemistry. 1988 ; Vol. 27, No. 7. pp. 2425-2430.
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