Novel approach reveals localisation and assembly pathway of the PsbS and PsbW proteins into the photosystem II dimer.
A blue-native gel electrophoresis system was combined with an in organello import assay to specifically analyse the location and assembly of two nuclear-encoded photosystem II (PSII) subunits. With this method we were able to show that initially the low molecular mass PsbW protein is not associated with the monomeric form of PSII. Instead a proportion of newly imported PsbW is directly assembled in dimeric PSII supercomplexes with very fast kinetics; its negatively charged N-terminal domain is essential for this process. The chlorophyll-binding PsbS protein, which is involved in energy dissipation, is first detected in the monomeric PSII subcomplexes, and only at later time points in the dimeric form of PSII. It seems to be bound tighter to the PSII core complex than to light harvesting complex II. These data point to radically different assembly pathways for different PSII subunits.
Thidholm
Ellinor
E
Arrhenius Laboratories for Natural Sciences, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91, Stockholm, Sweden.
Lindström
Viktoria
V
Tissier
Christophe
C
Robinson
Colin
C
Schröder
Wolfgang P
WP
Funk
Christiane
C
D002736:Chloroplasts / Q000378:metabolism*; D019281:Dimerization; D004591:Electrophoresis, Polyacrylamide Gel; D045342:Light-Harvesting Protein Complexes; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D018532:Pisum sativum / Q000378:metabolism*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism*; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D013997:Time Factors
D045342:Light-Harvesting Protein Complexes; D008565:Membrane Proteins; D009687:Nuclear Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins