PMID: 12911312

 

    Legend: Gene, Sites

Title : Mass spectrometric identification of N- and O-glycosylation sites of full-length rat selenoprotein P and determination of selenide-sulfide and disulfide linkages in the shortest isoform

Abstract :
  1. Rat selenoprotein P is an extracellular glycoprotein of 366 amino acid residues that is rich in cysteine and selenocysteine
  2. Plasma contains four isoforms that differ principally by length at the C-terminal end
  3. Mass spectrometry was used to identify sites of glycosylation on the full-length protein
  4. Of the potential N-glycosylation sites , three located at residues 64, 155, and 169 were occupied, while the two at residues 351 and 356 were not occupied
  5. Threonine 346 was variably O-glycosylated
  6. Thus, full-length selenoprotein P is both N- and O-glycosylated
  7. The shortest isoform of selenoprotein P isoform of selenoprotein P, which terminates at residue 244 , was analyzed for selenide-sulfide and disulfide linkages
  8. In this isoform , a single selenocysteine and seven cysteines are present
  9. Mass spectrometric analysis indicated that a selenide-sulfide bond exists between Sec40 and Cys43
  10. Two disulfides were also detected as Cys149-Cys167 and Cys153-Cys156
  11. The finding of a selenide-sulfide bond in the shortest isoform is compatible with a redox function of this pair that might be analogous to the selenol-thiol pair near the C terminus of animal thioredoxin reductase
  12. The disulfide formed by Cys153-Cys156 also has some characteristics of a redox active pair
Output (sent_index, trigger, protein, sugar, site):
  • 0. N-, , -, -, sites
  • 0. O-glycosylation, , selenoprotein P, -, -
  • 1. glycoprotein, , Rat selenoprotein P, -, -
  • 1. glycoprotein, , glycoprotein, -, -
  • 3. glycosylation, , -, -, sites
  • 4. N-glycosylation, , -, -, sites
  • 4. occupied, , -, -, residues 351 and 356
  • 5. O-glycosylated, , -, -, Threonine 346
Output(Part-Of) (sent_index, protein, site):
  • 1. Rat selenoprotein P, cysteine
  • 1. glycoprotein, cysteine
  • 11. thioredoxin reductase, terminus
  • 3. protein, sites
  • 8. isoform, cysteines
*Output_Site_Fusion* (sent_index, protein, sugar, site):
  • 5. selenoprotein P, -, Threonine 346

 

 

Protein NCBI ID SENTENCE INDEX
isoform of selenoprotein P 29360 7
Rat selenoprotein P 29360 1
selenoprotein P 29360 0,6