Removal of the 33, 23 and 18 kDa extrinsic proteins of photosystem II by sulfite treatment at alkaline pH.
We found that sulfite incubation of photosystem II submembrane fractions can induce selective depletion of the 18, 23 and 33 kDa polypeptides of the PSII oxygen evolving complex. When the sulfite treatment was done at pH 8.0, the 18 and 23 kDa proteins were removed efficiently from the PSII oxygen evolving complex. Under the same conditions, the 33 kDa subunit remained bound (even when 2 M sodium sulfite was used). However, in more alkaline conditions (pH 9.8), we show extensive removal of the 33 kDa in the presence of a low sulfite concentration (50 mM). The different extraction affinity for the 18, 23 and 33 kDa of the photosystem II complex was interpreted to mean that the 33 kDa polypeptides are bound to photosystem II by both electrostatic and hydrogen bonding forces.
Beauregard
M
M
Centre de recherche en photobiophysique, Université du Québec, Trois-Rivières, Canada.
Morin
L
L
Popovic
R
R
D002734:Chlorophyll / Q000302:isolation & purification / Q000378:metabolism*; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D045342:Light-Harvesting Protein Complexes; D008970:Molecular Weight; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D013347:Subcellular Fractions / Q000378:metabolism; D013447:Sulfites / Q000494:pharmacology*
D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D013447:Sulfites; D002734:Chlorophyll