Abstract
Long-range chiral organization of the pigment-protein complexes in mature granal chloroplasts has been established by differential polarization imaging and local circular dichroism spectra. Linear and circular dichroism images of oriented chloroplasts were obtained in a confocal differential polarization microscope. The circular dichroism images display signals of opposite signs emerging from discrete regions with local dichroic values much larger than anticipated, indicating domains in the thylakoid membranes having long-range chiral organization. These domains are associated with positive and negative circular dichroism bands obtained at specific locations on the chloroplasts. Surprisingly, the local circular dichroism spectra do not display the excitonic shape of spectra obtained for macroscopic suspensions, but the latter can be produced by superposition of two local spectra of opposite sign. These data are evidence for the existence of long-range chiral order of the pigment-protein complexes in thylakoid membranes. The possible role of the long-range chiral domains in the efficiency of energy delocalization through the thylakoid membranes is discussed.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Beach D. A., Bustamante C., Wells K. S., Foucar K. M. Differential polarization imaging. III. Theory confirmation. Patterns of polymerization of hemoglobin S in red blood sickle cells. Biophys J. 1987 Dec;52(6):947–954. doi: 10.1016/S0006-3495(87)83287-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Faludi-Dániel A., Mustárdy L. A. Organization of Chlorophyll a in the Light-Harvesting Chlorophyll a/b Protein Complex as Shown by Circular Dichroism : Liquid Crystal-Like Domains. Plant Physiol. 1983 Sep;73(1):16–19. doi: 10.1104/pp.73.1.16. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gagliano A. G., Geacintov N. E., Breton J. Orientation and linear dichroism of chloroplasts and sub-chloroplast fragments oriented in an electric field. Biochim Biophys Acta. 1977 Sep 14;461(3):460–474. doi: 10.1016/0005-2728(77)90233-x. [DOI] [PubMed] [Google Scholar]
- Garab G., Wells S., Finzi L., Bustamante C. Helically organized macroaggregates of pigment-protein complexes in chloroplasts: evidence from circular intensity differential scattering. Biochemistry. 1988 Aug 9;27(16):5839–5843. doi: 10.1021/bi00416a003. [DOI] [PubMed] [Google Scholar]
- Geacintov N. E., Van Norstrand F., Becker J. F., Tinkel J. B. Magnetic field induced orientation of photosynthetic systems. Biochim Biophys Acta. 1972 Apr 20;267(1):65–79. doi: 10.1016/0005-2728(72)90138-7. [DOI] [PubMed] [Google Scholar]
- Kim M., Keller D., Bustamante C. Differential polarization imaging. I. Theory. Biophys J. 1987 Dec;52(6):911–927. doi: 10.1016/S0006-3495(87)83285-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kim M., Ulibarri L., Bustamante C. Differential polarization imaging. II. Symmetry properties and calculations. Biophys J. 1987 Dec;52(6):929–946. doi: 10.1016/S0006-3495(87)83286-1. [DOI] [PMC free article] [PubMed] [Google Scholar]