Cyanobacteria express large quantities of the iron stress-inducible protein IsiA under iron deficiency. IsiA can assemble into numerous types of single or double rings surrounding Photosystem I. These supercomplexes are functional in light-harvesting, empty IsiA rings are effective energy dissipaters. Electron microscopy studies of these supercomplexes show that Photosystem I trimers bind 18 IsiA copies in a single ring, whereas monomers may bind up to 35 copies in two rings. Work on mutants indicates that the PsaF/J and PsaL subunits facilitate the formation of closed rings around Photosystem I monomers but are not obligatory components in the formation of Photosystem I-IsiA supercomplexes. © 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
Kouřil, R., Arteni, A. A., Lax, J., Yeremenko, N., D’Haene, S., Rögner, M., … Boekema, E. J. (2005, June 13). Structure and functional role of supercomplexes of IsiA and Photosystem I in cyanobacterial photosynthesis. FEBS Letters. https://doi.org/10.1016/j.febslet.2005.03.051