O-Glycosylation of G-protein-coupled receptor, octopus rhodopsin. Direct analysis by FAB mass spectrometry

FEBS Lett. 2001 May 4;496(1):19-24. doi: 10.1016/s0014-5793(01)02392-4.


In addition to the N-glycan that is evidently conserved in G-protein-coupled receptors (GPCRs), O-glycans in the N-terminus of GPCRs have been suggested. Using a combination of enzymatic and manual Edman degradation in conjunction with G-protein coupled receptor mass spectrometry, the structure and sites of O-glycans in octopus rhodopsin are determined. Two N-acetylgalactosamine residues are O-linked to Thr4 and Thr5 in the N-terminus of octopus rhodopsin. Further, we found chicken iodopsin, but not bovine rhodopsin, contains N-acetylgalactosamine. This is the first direct evidence to determine the structure and sites of O-glycans in GPCRs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carbohydrate Sequence
  • Cattle
  • Chickens
  • GTP-Binding Proteins* / metabolism
  • Glycosylation
  • Molecular Sequence Data
  • Octopodiformes
  • Polysaccharides / chemistry*
  • Receptors, Cell Surface / chemistry*
  • Receptors, Cell Surface / metabolism
  • Rhodopsin / chemistry*
  • Rhodopsin / metabolism
  • Sequence Analysis, Protein
  • Sequence Homology, Amino Acid
  • Spectrometry, Mass, Fast Atom Bombardment


  • Polysaccharides
  • Receptors, Cell Surface
  • Rhodopsin
  • GTP-Binding Proteins