Abstract
The organization of Arabidopsis thaliana photosystem II (PSII) and its associated light-harvesting antenna (LHCII) was studied in isolated PSII-LHCII supercomplexes and native membrane-bound crystals by transmission electron microscopy and image analysis. Over 4000 single-particle projections of PSII-LHCII supercomplexes were analyzed. In comparison to spinach supercomplexes [Boekema, E.J., van Roon, H., van Breemen, J.F.L. & Dekker, J.P. (1999) Eur. J. Biochem. 266, 444-452] some striking differences were revealed: a much larger number of supercomplexes from Arabidopsis contain copies of M-type LHCII trimers. M-type trimers can also bind in the absence of the more common S-type trimers. No binding of l-type trimers could be detected. Analysis of native membrane-bound PSII crystals revealed a novel type of crystal with a unit cell of 25.6 x 21.4 nm (angle 77 degrees ), which is larger than any of the PSII lattices observed before. The data show that the unit cell is built up from C2S2M2 supercomplexes, rather than from C2S2M supercomplexes observed in native membrane crystals from spinach [Boekema, E.J., Van Breemen, J.F.L., Van Roon, H. & Dekker, J.P. (2000) J. Mol. Biol. 301, 1123-1133]. It is concluded from both the single particle analysis and the crystal analysis that the M-type trimers bind more strongly to PSII core complexes in Arabidopsis than in spinach.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
