Glycosyl-phosphatidylinositol moiety that anchors Trypanosoma brucei variant surface glycoprotein to the membrane

• Published in: Science (American Association for the Advancement of Science) Vol. 239; no. 4841; pp. 753 - 759
• Main Authors: Ferguson, M.A.J, Homans, S.W, Dwek, R.A, Rademacher, T.W
• Format: Journal Article
• Language: English
• Published: Washington, DC The American Association for the Advancement of Science 12.02.1988; American Association for the Advancement of Science
• Subjects: Animals; Biochemistry; BIOLOGIA MOLECULAR; Biological and medical sciences; BIOLOGIE MOLECULAIRE; Carbohydrate Conformation; Carbohydrate Sequence; Carbohydrates - analysis; Cell Membrane - metabolism; Cell membranes; Cell membranes. Ionic channels. Membrane pores; CELL STRUCTURE; Cell structures and functions; cell surface; Connectivity; ESTRUCTURA CELULAR; Fractions; Functional groups; Fundamental and applied biological sciences. Psychology; GLICOPROTEINAS; GLYCOPROTEINE; GLYCOPROTEINS; glycosylphosphatidylinositol; Magnetic Resonance Spectroscopy; Mass Spectrometry; Membrane glycoproteins; Membrane proteins; Methylation; Molecular and cellular biology; MOLECULAR BIOLOGY; Molecular Sequence Data; Oxidation; Phosphates; Phosphatidylinositols - analysis; plasma membranes; Polysaccharides; Polysaccharides - analysis; Protons; STRUCTURE CELLULAIRE; TRYPANOSOMA; Trypanosoma brucei; Trypanosoma brucei brucei - metabolism; Variant Surface Glycoproteins, Trypanosoma - metabolism; Protozoa; Chemical modification; Membrane protein; Plasma membrane; Rhizoflagellata; Enzymatic digestion; Membrane surface; Glycoproteins; NMR spectrometry; Trypanosoma brucei; Mass spectrometry
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.3340856

Two forms of protein-membrane anchor have been described for the externally disposed glycoproteins of eukaryotic plasma membranes; namely, the hydrophobic transmembrane polypeptide and the complex glycosyl-phosphatidylinositol (G-PI) moiety. The chemical structures of the major species of G-PI anchors found on a single variant surface glycoprotein (VSG) of the parasitic protozoan Trypanosoma brucei were determined by a combination of nuclear magnetic resonance spectroscopy, mass spectrometry, chemical modification, and exoglycosidase digestions. The G-PI anchor was found to be heterogeneous with respect to monosaccharide sequence, and several novel glycosidic linkages were present. The results are pertinent to the mechanism of the biosynthesis of G-PI anchors.