title: Structure of the glycosyl-phosphatidylinositol membrane anchor of the Leishmania major promastigote surface protease.
abstract: 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.
authors: Institut de Biochimie, Université de Lausanne, Epalinges, Switzerland.
authors: P
authors: P
authors: Schneider
authors: M A
authors: MA
authors: Ferguson
authors: M J
authors: MJ
authors: McConville
authors: A
authors: A
authors: Mehlert
authors: S W
authors: SW
authors: Homans
authors: C
authors: C
authors: Bordier
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002462:Cell Membrane / Q000201:enzymology; D010450:Endopeptidases / Q000096:biosynthesis / Q000235:genetics*; D006017:Glycolipids / Q000096:biosynthesis* / Q000302:isolation & purification; D017261:Glycosylphosphatidylinositols; D007895:Leishmania tropica / Q000201:enzymology* / Q000235:genetics; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D008969:Molecular Sequence Data; D019814:Myristic Acid; D009227:Myristic Acids / Q000378:metabolism; D010716:Phosphatidylinositols / Q000096:biosynthesis* / Q000302:isolation & purification; D012689:Sequence Homology, Nucleic Acid; D014346:Trypanosoma brucei brucei / Q000235:genetics; D014643:Variant Surface Glycoproteins, Trypanosoma / Q000235:genetics
chemical_list: D006017:Glycolipids; D017261:Glycosylphosphatidylinositols; D009227:Myristic Acids; D010716:Phosphatidylinositols; D014643:Variant Surface Glycoproteins, Trypanosoma; D019814:Myristic Acid; D010450:Endopeptidases