Identification of a 19-kDa polypeptide as an Fe-S center apoprotein in the photosystem I primary electron acceptor complex.
Treatment of Photosystem I (PSI) with sodium thiocyanate, a chaotropic agent, results in the selective depletion of certain low-molecular-weight polypeptides. A PSI complex obtained following treatment with 0.5 M sodium thiocyanate is significantly depleted of polypeptides of approximately 8, 10, 14, and 16 kDa, relative to an untreated control, but retains approximately 90% of the EPR signal amplitude associated with the iron-sulfur Centers A and B. The only peptides remaining that could not be depleted without a parallel decrease in the signal amplitude of the Fe-S Centers A and B are the 62-kDa reaction center-containing polypeptide and a 19-kDa polypeptide. These results are considered in relation to the identity of the apoprotein of the Fe-S Centers A and B.
Bonnerjea
J
J
Ortiz
W
W
Malkin
R
R
D001059:Apoproteins / Q000145:classification / Q000302:isolation & purification*; D002734:Chlorophyll / Q000378:metabolism*; D003720:Densitometry; D004578:Electron Spin Resonance Spectroscopy; D004591:Electrophoresis, Polyacrylamide Gel; D007506:Iron-Sulfur Proteins / Q000378:metabolism*; D045342:Light-Harvesting Protein Complexes; D008667:Metalloproteins / Q000378:metabolism*; D008970:Molecular Weight; D010455:Peptides / Q000145:classification / Q000378:metabolism*; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D010940:Plant Proteins / Q000378:metabolism*; D013861:Thiocyanates
D001059:Apoproteins; D007506:Iron-Sulfur Proteins; D045342:Light-Harvesting Protein Complexes; D008667:Metalloproteins; D010455:Peptides; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D010940:Plant Proteins; D013861:Thiocyanates; D002734:Chlorophyll; C024553:sodium thiocyanate