tailieunhanh - Báo cáo khoa học: Mucin-type O-glycosylation – putting the pieces together

The O-glycosylation of Ser and Thr by N-acetylgalactosamine-linked (mucin-type) oligosaccharides is often overlooked in protein analysis. Three characteristics make O-linked glycosylation more difficult to analyse than N-linked glycosylation, namely: (a) no amino acid consensus sequence is known | ỊFEBS Journal REVIEW ARTICLE Mucin-type O-glycosylation - putting the pieces together Pia H. Jensen Daniel Kolarich and Nicolle H. Packer Department of Chemistry and Biomolecular Sciences Faculty of Science Biomolecular Frontiers Research Centre Macquarie University Sydney Australia Keywords electron transfer dissociation ETD electron capture dissociation ECD glycopeptides MS mucin oligosaccharides O-glycosylation released glycans site specificity Correspondence N. Packer Department of Chemistry and Biomolecular Sciences Faculty of Science Biomolecular Frontiers Research Centre Macquarie University Building E8C Room 307 Sydney NSW 2109 Australia Fax 61 2 9850 8313 Tel 61 2 98508176 E-mail Website http academics The O-glycosylation of Ser and Thr by N-acetylgalactosamine-linked mucin-type oligosaccharides is often overlooked in protein analysis. Three characteristics make O-linked glycosylation more difficult to analyse than N-linked glycosylation namely a no amino acid consensus sequence is known b there is no universal enzyme for the release of O-glycans from the protein backbone and c the density and number of occupied sites may be very high. For significant biological conclusions to be drawn the complete picture of O-linked glycosylation on a protein needs to be determined. This review specifically addresses the analytical approaches that have been used and the challenges remaining in the characterization of both the composition and structure of mucin-type O-glycans and the determination of the occupancy and heterogeneity at each amino acid attachment site. Received 12 June 2009 revised 3 September 2009 accepted 11 September 2009 doi Introduction Protein glycosylation is known to be involved in cellular targeting and secretion 1 . It can also help to regulate enzymatic activity confer enhanced stability and solubility to secreted proteins and affect the functionality of .