Proteomic approach to characterize the supramolecular organization of photosystems in higher plants

authored by
Jesco Heinemeyer, Holger Eubel, Dirk Wehmhöner, Lothar Jänsch, Hans Peter Braun
Abstract

A project to investigate the supramolecular structure of photosystems was initiated, which is based on protein solubilizations by digitonin, protein separations by Blue native (BN)-polyacrylamide gel electrophoresis (PAGE) and protein identifications by mass spectrometry (MS). Under the conditions applied, nine photosystem supercomplexes could be described for chloroplasts of Arabidopsis, which have apparent molecular masses between 600 and 3200 kDa on BN gels. Identities of the supercomplexes were determined on the basis of their subunit compositions as documented by 2D BN/SDS-PAGE and BN/BN-PAGE. Two supercomplexes of 1060 and ∼1600 kDa represent dimeric and trimeric forms of photosystem I (PSI), which include tightly bound LHCI proteins. Compared to monomeric PSI, these protein complexes are of low abundance. In contrast, photosystem II mainly forms part of dominant supercomplexes of 850, 1000, 1050 and 1300 kDa. According to our interpretation, these supercomplexes contain dimeric PSII, 1-4 LHCII trimers and additionally monomeric LHCII proteins. The 1300-kDa PSII supercomplex (containing four LHCII trimers) is partially converted into the 1000-kDa PSII supercomplex (containing two LHCII trimers) in the presence of dodecylmaltoside on 2D BN/BN gels. Analyses of peptides of the trypsinated 1300-kDa PSII supercomplex by mass spectrometry allowed to identify known subunits of the PSII core complex and additionally LHCII proteins encoded by eight different genes in Arabidopsis. Further application of this experimental approach will allow new insights into the supermolecular organization of photosystems in plants.

Organisation(s)
Institute of Plant Genetics
External Organisation(s)
Helmholtz Centre for Infection Research (HZI)
Type
Article
Journal
PHYTOCHEMISTRY
Volume
65
Pages
1683-1692
No. of pages
10
ISSN
0031-9422
Publication date
21.05.2004
Publication status
Published
Peer reviewed
Yes
ASJC Scopus subject areas
Biochemistry, Molecular Biology, Plant Science, Horticulture
Electronic version(s)
https://doi.org/10.1016/j.phytochem.2004.04.022 (Access: Unknown)