Photosystem I reaction-centre proteins contain leucine zipper motifs. A proposed role in dimer formation.
The photosystem I (PS I) reaction-centre polypeptides, encoded by the psaA and psaB genes, are shown to contain several highly conserved leucine repeats, consisting of a leucine residue every seventh amino acid, similar to the leucine zipper motifs known to mediate DNA-binding polypeptide dimerisation. In each of the PSI reaction-centre subunits the leucine zipper motif precedes highly conserved cysteine residues which have been proposed to ligate the interpolypeptide [4Fe-4S] centre, Fx. We propose that PS I reaction-centre dimerisation and [4Fe-4S] centre formation are mediated through the leucine zipper.
Webber
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AN
Department of Plant Biology, University of California, Berkeley 94720.
Malkin
R
R
D000595:Amino Acid Sequence; D002734:Chlorophyll / Q000235:genetics*; D017343:Genes, Plant; D007930:Leucine; D045342:Light-Harvesting Protein Complexes; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D010940:Plant Proteins / Q000235:genetics*; D010944:Plants / Q000235:genetics; D011487:Protein Conformation; D012689:Sequence Homology, Nucleic Acid
D045342:Light-Harvesting Protein Complexes; D046911:Macromolecular Substances; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D010940:Plant Proteins; D002734:Chlorophyll; D007930:Leucine