tailieunhanh - Báo cáo Y học: Tyrosine sulfation and N-glycosylation of human heparin cofactor II from plasma and recombinant Chinese hamster ovary cells and their effects on heparin binding

The structure of post-translational modifications of human heparin cofactor II isolated from human serum and from recombinant Chinese hamster ovary cells and their effects on heparin binding have been characterized. Oligosaccharide chains were found attached to all three potential N-glycosylation sites in both protein preparations. The carbohydrate structures of heparin cofactor II circulating in blood are complex-type diantennary and triantennary chains in a ratio of 6 : 1 with the galactose being 90% sialylated with a2 fi 6 linked N-acetylneuraminic acid | Eur. J. Biochem. 269 977-988 2002 FEBS 2002 Tyrosine sulfation and N-glycosylation of human heparin cofactor II from plasma and recombinant Chinese hamster ovary cells and their effects on heparin binding Christoph Bohme1 Manfred Nimtz2 Eckart Grabenhorst3 Harald S. Conradt3 Annemarie Strathmann1 and Hermann Ragg1 1Faculty of Technology University of Bielefeld Germany 2Molecular Structure Research and3 Protein Glycosylation Gesellschaft fur Biotechnologische Forschung mbH Braunschweig Germany The structure of post-translational modifications of human heparin cofactor II isolated from human serum and from recombinant Chinese hamster ovary cells and their effects on heparin binding have been characterized. Oligosaccharide chains were found attached to all three potential N-gly-cosylation sites in both protein preparations. The carbohydrate structures of heparin cofactor II circulating in blood are complex-type diantennary and triantennary chains in a ratio of 6 1 with the galactose being 90 sialylated with a2 6 linked N-acetylneuraminic acid. About 50 of the triantennary structures contain one sLex motif. Proximal al 6 fucosylation of oligosacharides from Chinese hamster ovary cell-derived HCII was detected in 90 of the diantennary and triantennary glycans the latter being slightly less sialylated with exclusively a2 3-linked N-acetylneuraminic acid units. Applying the ESI-MS MS-MS technique we demonstrate that the tryptic peptides comprising tyrosine residues in positions 60 and 73 were almost completely sulfated irrespective of the protein s origin. Treatment of transfected Chinese hamster ovary cells with chlorate or tunicamycin resulted in the production of heparin cofactor II molecules that eluted with higher ionic strength from heparin-Sepharose indicating that tyrosine sulfation and N-linked glycans may affect the inhibitor s interaction with glycosaminoglycans. Keywords heparin cofactor II glycosylation tyrosine sulfation heparin binding serpins. Heparin .