Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

Light-harvesting complex II pigments and proteins in association with Cbr, a homolog of higher-plant early light-inducible proteins in the unicellular green alga Dunaliella

Gabi Banet, Uri Pick and Ada Zamir
Planta
Vol. 210, No. 6 (May 2000), pp. 947-955
Published by: Springer
Stable URL: http://www.jstor.org/stable/23385932
Page Count: 9
  • More info
  • Cite this Item
Light-harvesting complex II pigments and proteins in association with Cbr, a homolog of higher-plant early light-inducible proteins in the unicellular green alga Dunaliella
Preview not available

Abstract

Like higher plants, unicellular green algae of the genus Dunaliella respond to light stress by enhanced de-epoxidation of violaxanthin and accumulation of Cbr, a protein homologous to early light-inducible proteins (Elips) in plants. Earlier studies indicated that Cbr was associated with the light-harvesting complex of photosystem II (LHCII) and suggested it acted as a zeaxanthin-binding protein and fulfilled a photo-protective function (Levy et al. 1993, J. Biol. Chem. 268: 20892—20896). To characterize the protein-pigment sub-complexes containing Cbr in greater detail than attained so far, thylakoid membranes from Dunaliella salina grown in high light or normal light were solubilized with dodecyl maltoside and fractionated by isoelectric-focusing. Analysis of the resolved LHCII subcomplexes indicated preferred associations among the four LHCIIb polypeptides and between them and Cbr: subcomplexes including Cbr contained one or two of the more acidic of the four LHCIIb polypeptides as well as large amounts of lutein and zeaxanthin relative to chlorophyll a/b. After sucrose gradient centrifugation, Cbr free of LHCIIb polypeptides was detected together with released pigments; this Cbr possibly originated in subcomplexes dissociated in the course of the analysis. These results agree with the conclusion that Cbr is part of the network of LHCIIb protein-pigment complexes and suggest that the role played by Cbr involves the organization and/or stabilization of assemblies highly enriched in zeaxanthin and lutein. Such assemblies may function to protect PSII from photodamage due to overexcitation.

Page Thumbnails

  • Thumbnail: Page 
[947]
    [947]
  • Thumbnail: Page 
948
    948
  • Thumbnail: Page 
949
    949
  • Thumbnail: Page 
950
    950
  • Thumbnail: Page 
951
    951
  • Thumbnail: Page 
952
    952
  • Thumbnail: Page 
953
    953
  • Thumbnail: Page 
954
    954
  • Thumbnail: Page 
955
    955