Structural and functional properties of the cyanobacterial photosystem I complex.
Photosystem I (PSI) complexes have been isolated from two cyanobacterial strains, Synechococcus sp. PCC 7002 and 6301. These complexes contain six to seven low molecular mass subunits in addition to the two high molecular mass subunits previously shown to bind the primary reaction center components. Chemical cross-linking of ferredoxin to the complex identified a 17.5-kDa subunit as the ferredoxin-binding protein in the Synechococcus sp. PCC 6301-PSI complex. The amino acid sequence of this subunit, deduced from the DNA sequence of the gene, confirmed its identity as the psaD gene product. A 17-kDa subunit cross-links to the electron donor, cytochrome c-553, in a manner analogous to the cross-linking of plastocyanin to the higher plant PSI complex. Using antibodies raised against the spinach psaC gene product (a 9-kDa subunit which binds Fe-S centers A and B), we identified an analogous protein in the cyanobacterial PSI complex.
Wynn
R M
RM
Division of Molecular Plant Biology, University of California, Berkeley 94720.
Omaha
J
J
Malkin
R
R
D000595:Amino Acid Sequence; D002734:Chlorophyll / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000458:Cyanobacteria / Q000235:genetics / Q000378:metabolism*; D005796:Genes; D045342:Light-Harvesting Protein Complexes; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D008970:Molecular Weight; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D010940:Plant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
D045342:Light-Harvesting Protein Complexes; D046911:Macromolecular Substances; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D010940:Plant Proteins; D002734:Chlorophyll