tailieunhanh - Báo cáo khoa học: N-Glycan structures of squid rhodopsin Existence of the a1–3 and a1–6 difucosylated innermost GlcNAc residue in a molluscan glycoprotein

To determine the glycoforms of squid rhodopsin, N-glycans were released by glycoamidase A digestion, reductively aminated with 2-aminopyridine, and then subjected to 2D HPLC analysis [Takahashi, N., Nakagawa, H., Fujikawa, K.,Kawamura,Y.&Tomiya,N. (1995)Anal. , 139–146]. Themajor glycans of squid rhodopsinwere shown to possess the a1–3 and a1–6 difucosylated innermost GlcNAc residue found in glycoproteins produced by insects and helminths. | Eur. J. Biochem. 270 2627-2632 2003 FEBS 2003 doi N-Glycan structures of squid rhodopsin Existence of the al-3 and al-6 difucosylated innermost GlcNAc residue in a molluscan glycoprotein Noriko Takahashi1 Katsuvoshi Masuda2. Kenji Hiraki2 Kazuo Yoshihara2 Huna-Hsiana Huana3. Kay-Hooi Khoo3 and Koichi Kato1 1Graduate School of Pharmaceutical Sciences Nagoya City University Japan 2Suntory Institute for Bioorganic Research Shimamoto-cho Mishima-gun Osaka Japan 3Institute of Biological Chemistry Academia Sinica Taipei Taiwan To determine the glycoforms of squid rhodopsin N-glycans were released by glycoamidase A digestion reductively aminated with 2-aminopyridine and then subjected to 2D HPLC analysis Takahashi N. Nakagawa H. Fujikawa K. Kawamura Y. Tomiya N. 1995 Anal. Biochem. 226 139-146 . The major glycans of squid rhodopsin were shown to possess the a1-3 and a1-6 difucosylated innermost GlcNAc residue found in glycoproteins produced by insects and helminths. By combined use of 2D HPLC. electrospiriy ionization-mass spectrometry and permethylation and gas chromatography-electron ionization mass spectrometry analyses it was revealed that most 85 of the N-glycans exhibit the novel structure Mana1-6 Mana1-3 Manb1-4GlcNAcp1-4 Galp1-4Fuca1-6 Fuca1-3 GlcNAc. Keywords 2D HPLC mapping mass spectrometry N-gly-can structures rhodopsin squid. Rhodopsin the visual pigment in the photoreceptor cells is a typical seven transmembrane receptor and has been widely studied to elucidate the mechanisms of a visual transduction cascade 1 2 . The N-terminal segment of rhodopsin is N-glycosylated. It has been reported that the carbohydrate moieties contribute to the integrity of rhodopsin functions and abnormalities in the N-glycosylation of rhodopsin are associated with autosomal dominant retinitis pigmentosa 3-8 . The rhodopsin N-glycan structures have so far been determined for bovine 9 10 frog 11 human 12 rat 13 and octopus 14 . Mammalian and frog .