O-Glycosylation of G-protein-coupled receptor, octopus rhodopsin. Direct analysis by FAB mass spectrometry.
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.
Nakagawa
M
M
Department of Life Sciences, Himeji Institute of Technology, Harima Science Garden City, Hyogo, Japan.
Miyamoto
T
T
Kusakabe
R
R
Takasaki
S
S
Takao
T
T
Shichida
Y
Y
Tsuda
M
M
D000818:Animals; D002240:Carbohydrate Sequence; D002417:Cattle; D002645:Chickens; D019204:GTP-Binding Proteins / Q000378:metabolism; D006031:Glycosylation; D008969:Molecular Sequence Data; D049831:Octopodiformes; D011134:Polysaccharides / Q000737:chemistry*; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000378:metabolism; D012243:Rhodopsin / Q000737:chemistry* / Q000378:metabolism; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D016339:Spectrometry, Mass, Fast Atom Bombardment
D011134:Polysaccharides; D011956:Receptors, Cell Surface; D012243:Rhodopsin; D019204:GTP-Binding Proteins