Table I.

Identification of C670-associated proteins by mass spectrometry

BandIdentified ProteinProtein FamilyAccession No.Unique PeptidesPredicted Molecular MassaObserved Molecular Massb
1SSIIIStarch synthase30571208188200
1ACCIAAcetyl-CoA carboxylase322649404257200
2SSIIIStarch synthase30571207188175
2UnknowncClathrin heavy chain11548373724192175
3SSIIIStarch synthase30571208188150
3UnknowncSpliceosomal-like protein1255807412135150
4SSIIIStarch synthase30571205188140
4Unknownc26S proteosome subunit1163101187109140
4UnknowncRNA-binding protein RP1201154464112108140
5PPDK1Pyruvate orthophosphate dikinase1938063579d95e105
5PPDK2Pyruvate orthophosphate dikinaseTA164186_45776f95e105
5Unknownc26S proteosome subunit115444199498105
5UnknowncCell division cycle protein CDC48110289141490105
6Unknownc26S proteosome subunit1154441991098100
6UnknowncCell division cycle protein CDC48110289141390100
6UnknowncPutative initiation factor eIF-3b115483552283100
7UnknowncStromal HSP7011548799877473
7UnknowncStromal HSP7011544095567173
7UnknowncStromal HSP7012559366037373
  • a Molecular mass values of full-length proteins are indicated (i.e. before removal of plastid or other targeting sequences), unless otherwise indicated.

  • b Observed molecular mass values were estimated based on comparison with those of known standard proteins (Fig. 5).

  • c Unknown proteins are those for which maize cDNA or genomic DNA sequences are not yet included in the public data set. Protein family assignment is made based on identity between the peptide sequences and known protein sequences from rice, together with BLAST analysis to identify related proteins in other species. Database accession numbers are for the predicted rice protein.

  • d Five peptides are perfect matches with PPDK1, and four are perfect matches to both PPDK1 and PPDK2.

  • e Predicted molecular mass is for the mature protein after cleavage of the plastid-targeting peptide.

  • f Three peptides are perfect matches with PPDK2, and three are perfect matches to both PPDK1 and PPDK2.