Structural characterization of the oligosaccharide chains of human α1- microglobulin from urine and amniotic fluid

Angela Amoresano, Lorenzo Minchiotti, Maria E. Cosulich, Monica Campagnoli, Piero Pucci, Annapaola Andolfo, Elisabetta Gianazza, Monica Galliano

Research output: Contribution to journalArticlepeer-review

Abstract

Human α1-microglobulin (α1-m; also called protein HC), a glycoprotein belonging to the lipocalin superfamily, was isolated by sequential anion-exchange chromatography and gel filtration from the urine of hemodialized patients and from amniotic fluid collected in the week 16-18 of pregnancy. The carbohydrate chains of the protein purified from the two sources, which are organized in two Asn-linked and one Thr-linked oligosaccharides, were structurally characterized using matrix-assisted laser desorption ionization and electrospray mass spectrometry. The glycans attached to Thr5 are differently truncated NeuHexHexNAc sequences, and O- glycosylation in the amniotic fluid protein is only partial. Asn96 has both diantennary and triantennary structures attached in the case of urinary α1- m and only diantennary glycans in the amniotic fluid protein. The main carbohydrate units attached to Asn17 are in both proteins monosialylated and disialylated diantennary glycans. The position of the oligosaccharide chains in a three-dimensional model of the protein, produced using the automated Swiss-Model service, is also discussed.

Original languageEnglish
Pages (from-to)2105-2112
Number of pages8
JournalEuropean Journal of Biochemistry
Volume267
Issue number7
DOIs
Publication statusPublished - 2000

Keywords

  • α-microglobulin
  • Lipocalins
  • Mass spectrometry
  • Oligosaccharide structure

ASJC Scopus subject areas

  • Biochemistry

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