9
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: not found

      Role of thylakoid lipids in the structural flexibility of lamellar aggregates of the isolated light-harvesting chlorophyll a/b complex of photosystem II.

      Biochemistry
      Chlorophyll, chemistry, physiology, Chloroplasts, ultrastructure, Circular Dichroism, Diglycerides, Galactolipids, Glycolipids, Light-Harvesting Protein Complexes, Lipid Bilayers, Macromolecular Substances, Microscopy, Electron, Peas, Photosynthetic Reaction Center Complex Proteins, Photosystem II Protein Complex

      Read this article at

      ScienceOpenPublisherPubMed
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          We studied the role of added thylakoid lipids in the light-induced reversible structural changes in isolated macroaggregates of the main light-harvesting chlorophyll a/b complex of photosystem II (LHCII). Loosely stacked lamellar macroaggregates were earlier shown to undergo light-induced reversible structural changes and changes in the photophysical pathways, which resembled those in thylakoid membranes exposed to excess light [Barzda, V., et al. (1996) Biochemistry 35, 8981-8985]. This structural flexibility of LHCII depends critically on the lipid content of the preparations [Simidjiev, I., et al. (1997) Anal. Biochem. 250, 169-175]. It is now reported that lamellar aggregates of LHCII are capable of incorporating substantial amounts of different thylakoid lipids. The long-range order of the chromophores is retained, while the ultrastructure of the lipid-protein macroaggregates can be modified significantly. Addition of thylakoid lipids to the preparations significantly enhances the ability of the LHCII macroaggregates to undergo light-induced structural changes. The lipid environment of the LHCII complexes therefore plays a significant role in determining the structural flexibility of the macroaggregates. As concerns the mechanism of these changes, it is proposed that the absorption of light and the dissipation of its energy in the macrodomains induces thermal fluctuations which bring about changes in the shape or in the stacking interactions of the membranes, this in turn affecting the long-range order of the embedded chromophores. In thylakoids, a similar mechanism is likely to explain the light-induced structural changes which are largely independent of the photochemical activity of the membranes.

          Related collections

          Author and article information

          Comments

          Comment on this article