Structure of the glycosyl-phosphatidylinositol membrane anchor of the Leishmania major promastigote surface protease

• Published in: The Journal of biological chemistry Vol. 265; no. 28; pp. 16955 - 16964
• Main Authors: Schneider, P, Ferguson, M A, McConville, M J, Mehlert, A, Homans, S W, Bordier, C
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 05.10.1990; American Society for Biochemistry and Molecular Biology
• Subjects: Amino Acid Sequence; Animals; Carbohydrate Conformation; Carbohydrate Sequence; Cell Membrane - enzymology; Endopeptidases - biosynthesis; Endopeptidases - genetics; Glycolipids - biosynthesis; Glycolipids - isolation & purification; Glycosylphosphatidylinositols; Leishmania tropica - enzymology; Leishmania tropica - genetics; Magnetic Resonance Spectroscopy; Methylation; Molecular Sequence Data; Myristic Acid; Myristic Acids - metabolism; phosphatidylinositol; Phosphatidylinositols - biosynthesis; Phosphatidylinositols - isolation & purification; promastigote surface proteinase; Sequence Homology, Nucleic Acid; Trypanosoma brucei brucei - genetics; Variant Surface Glycoproteins, Trypanosoma - genetics
• DOI: 10.1016/S0021-9258(17)44853-8
• ISSN: 0021-9258

In common with many other plasma membrane glycoproteins of eukaryotic origin, the promastigote surface protease (PSP) of the protozoan parasite Leishmania contains a glycosyl-phosphatidylinositol (GPI) membrane anchor. The GPI anchor of Leishmania major PSP was purified following proteolysis of the PSP and analyzed by two-dimensional 1H-1H NMR, compositional and methylation linkage analyses, chemical and enzymatic modifications, and amino acid sequencing. From these results, the structure of the GPI-containing peptide was found to be Asp-Gly-Gly-Asn-ethanolamine-PO4-6Man alpha 1-6Man alpha 1-4GlcN alpha 1-6myo-inositol-1-PO4-(1-alkyl-2-acyl-glycerol). The glycan structure is identical to the conserved glycan core regions of the GPI anchor of Trypanosoma brucei variant surface glycoprotein and rat brain Thy-1 antigen, supporting the notion that this portion of GPIs are highly conserved. The phosphatidylinositol moiety of the PSP anchor is unusual, containing a fully saturated, unbranched 1-O-alkyl chain (mainly C24:0) and a mixture of fully saturated unbranched 2-O-acyl chains (C12:0, C14:0, C16:0, and C18:0). This lipid composition differs significantly from those of the GPIs of T. brucei variant surface glycoprotein and mammalian erythrocyte acetylcholinesterase but is similar to that of a family of glycosylated phosphoinositides found uniquely in Leishmania.