Structural and functional self-organization of Photosystem II in grana thylakoids.
The biogenesis of the well-ordered macromolecular protein arrangement of photosystem (PS)II and light harvesting complex (LHC)II in grana thylakoid membranes is poorly understood and elusive. In this study we examine the capability of self organization of this arrangement by comparing the PSII distribution and antenna organization in isolated untreated stacked thylakoids with restacked membranes after unstacking. The PS II distribution was deduced from freeze-fracture electron microscopy. Furthermore, changes in the antenna organization and in the oligomerization state of photosystem II were monitored by chlorophyll a fluorescence parameters and size analysis of exoplasmatic fracture face particles. Low-salt induced unstacking leads to a randomization and intermixing of the protein complexes. In contrast, macromolecular PSII arrangement as well as antenna organization in thylakoids after restacking by restoring the original solvent composition is virtually identical to stacked control membranes. This indicates that the supramolecular protein arrangement in grana thylakoids is a self-organized process.
Kirchhoff
Helmut
H
Institut für Botanik, Schlossgarten 3, D-48149 Münster, Germany. kirchhh@uni-muenster.de
Haase
Winfried
W
Haferkamp
Silvia
S
Schott
Thomas
T
Borinski
Mauricio
M
Kubitscheck
Ulrich
U
Rögner
Matthias
M
D000818:Animals; D002734:Chlorophyll / Q000737:chemistry; D005614:Freeze Fracturing; D008854:Microscopy, Electron; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D011506:Proteins / Q000737:chemistry; D013053:Spectrophotometry / Q000379:methods; D018724:Spinacia oleracea; D013696:Temperature; D020524:Thylakoids / Q000378:metabolism*; D013997:Time Factors
D045332:Photosystem II Protein Complex; D011506:Proteins; D002734:Chlorophyll