Document Detail


Expression of a novel cell surface lipophosphoglycan-like glycoconjugate in Trypanosoma cruzi epimastigotes.
MedLine Citation:
PMID:  8071317     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The lipophosphoglycan (LPG)-like glycoconjugate expressed on the cell surface of Trypanosoma cruzi epimastigotes was isolated, purified, and partially characterized. The glycoconjugate migrated as a homogeneous band (42 kDa) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Matrix-assisted laser desorption ionization mass spectral analysis of the native molecule indicated the presence of two major components whose molecular masses were about 18.4 and 22.5 kDa. The LPG could be metabolically labeled with [3H]galactose, [3H]mannose, [14C]glucose, or [3H]palmitic acid. Monosaccharide compositional analysis of the LPG indicated that galactose, glucosamine, and sialic acid predominate over mannose, galactosamine, and inositol. A peptide associated with the LPG molecule contained about 40 amino acid residues per inositol and had threonine as the predominant amino acid. The LPG showed strong binding to Ricinus communis agglutinin-1 and Tritium vulgare wheat germ agglutinin, indicating the presence of terminal beta 1,4-linked galactosyl residue(s) and N-acetylglucosamine, respectively. Lectin binding studies also suggested the presence of a terminal beta-galactose and GlcNAc in the glycan-inositol lipid core of LPG. Virtually all of the sialic acids appeared to be located in the saccharide portion of the molecule. Treatment of the LPG with phosphatidylinositol-specific phospholipase C liberated an alkylacylglycerol. Structural analysis of the alkylacylglycerol and its acidic methanolysis products by gas-liquid chromatography/mass spectrometry indicated that the glycerol substituents were primarily the C16 1-alkyl group and C16 2-acyl group. The ratio of inositol to 1-O-alkyl-2-O-acylglycerol was 1:1. Treatment of the glycoconjugate with nitrous acid released a major phospholipid product that migrated close to the phosphatidylinositol standard on thin layer chromatography. This result implied that phosphatidylinositol was glycosidically linked to the nonacetylated amino sugar. Furthermore, the LPG was found to contain phosphate and was labile to mild acid hydrolysis, strongly suggesting that the intact molecule is related to Leishmania LPG. The most striking and unique feature of T. cruzi LPG is the presence of large amounts of glucosamine and sialic acid as well as galactosamine. These results indicate that the glycoconjugate expressed on the T. cruzi cell surface is a new type of LPG-like molecule anchored on the cell surface via an alkylacylphosphatidylinositol.
Authors:
B N Singh; J J Lucas; D H Beach; C E Costello
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  269     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1994 Sep 
Date Detail:
Created Date:  1994-09-29     Completed Date:  1994-09-29     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  21972-82     Citation Subset:  IM    
Affiliation:
Department of Microbiology and Immunology, State University of New York Health Science Center, Syracuse 13210.
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MeSH Terms
Descriptor/Qualifier:
Animals
Carbohydrate Metabolism
Carbohydrate Sequence
Cell Membrane / metabolism
Chromatography, Affinity
Chromatography, Gas
Chromatography, Ion Exchange
Chromatography, Thin Layer
Deamination
Electrophoresis, Polyacrylamide Gel
Gas Chromatography-Mass Spectrometry / methods
Glycoconjugates / biosynthesis*
Glycosphingolipids / biosynthesis*
Hydrogen-Ion Concentration
Hydrolysis
Methane / metabolism
Molecular Sequence Data
Phosphatidylinositol Diacylglycerol-Lyase
Phosphoinositide Phospholipase C
Phosphoric Diester Hydrolases / metabolism
Trypanosoma cruzi / metabolism*
Grant Support
ID/Acronym/Agency:
NIAID AI-05802/AI/NIAID NIH HHS; RR-00317/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
0/Glycoconjugates; 0/Glycosphingolipids; 0/lipophosphonoglycan; 74-82-8/Methane; EC 3.1.4.-/Phosphoric Diester Hydrolases; EC 3.1.4.11/Phosphoinositide Phospholipase C; EC 4.6.1.13/Phosphatidylinositol Diacylglycerol-Lyase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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