Mucin-type O-glycosylation – putting the pieces together

Authors

  • Pia H. Jensen,

    1. Department of Chemistry and Biomolecular Sciences, Faculty of Science, Biomolecular Frontiers Research Centre, Macquarie University, Sydney, Australia
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  • Daniel Kolarich,

    1. Department of Chemistry and Biomolecular Sciences, Faculty of Science, Biomolecular Frontiers Research Centre, Macquarie University, Sydney, Australia
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  • Nicolle H. Packer

    1. Department of Chemistry and Biomolecular Sciences, Faculty of Science, Biomolecular Frontiers Research Centre, Macquarie University, Sydney, Australia
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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: nicki.packer@mq.edu.au
Website: http://www.chem.mq.edu.au/academics/npacker.html

Abstract

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.

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