Glycosylphosphatidylinositol structure

Silva et al. have developed a strategy for the synthesis of the branched GPI (glycosylphosphatidylinositol) structure (29) and demonstrated its utility as a surface antigen against monoclonal antibodies of T. gondiiP... 

A bacterial phosphatidylinositol specific phospholipase C (PI-PLC) had been available for many years before it was demonstrated to strip a number of membrane-bound proteins from eukaryotic cell surfaces [1], Such proteins are anchored by a PI moiety in which the 6 position of inositol is glycosidically linked to glucosamine, which in turn is bonded to a polymannan backbone (Fig. 3-10). The polysaccharide chain is joined to the carboxyl terminal of the anchored protein via amide linkage to ethanolamine phosphate. The presence of a free NH2 group in the glucosamine residue makes the structure labile to nitrous acid. Bacterial PI-PLC hydrolyzes the bond between DAG and phosphati-dylinositols, releasing the water-soluble protein polysac charide-inositol phosphate moiety. These proteins are tethered by glycosylphosphatidylinositol (GPI) anchors. 

Hundt, M., Schmidt, R.E. (1992). The glycosylphosphatidylinositol-linked Fc/receptor III represents the dominant receptor structure for immune complex activation of neutrophils. Eur. J. Immunol. 22, 811-16. 

Glycosylphosphatidylinositols (GPI anchors 14) are a class of naturally occu-ring glycophospholipids that do not only bind the C-termini of membrane protein but also mediate signal transduction. Several papers have been devoted to their syntheses. Most of them have a structure related to 14 (with various side-chains that are species-specific) but some yeast GPI have been reported to... 

To better understand the structural properties of the lipoproteins involved in intracellular signaling pathways, synthetic lipopeptides are required as model compounds. In this context, to bypass the enzyme-catalyzed lipidation occurring in nature, optimized synthetic procedures have been elaborated for the more simple lipo-derivatives (for comprehensive reviews see ref[1]). However, similar efficient synthetic procedures for the glycosylphosphatidylinositol anchor are still lacked. 

Scheme 13 Structure of the Natural Protein Membrane Anchor Glycosylphosphatidylinositol...

Figure 8-13 Structure of glycosylphosphatidylinositol (also called phospha-tidylinositol-glycan) membrane anchors. The core structure is shown in black. The green parts are found in the Thy-1 protein and / or in other anchors.

Structure and Nomenclature of Inositol Phosphates, Phosphoinositides, and Glycosylphosphatidylinositols... 

Low, 2000 Shears, 2001, 2004). Many of these will be detailed in the rest of this book. In this chapter, I will introduce the structural, stereochemical, conformational, and nomenclature aspects of inositol phosphates, phosphatidyli-nositides, and glycosylphosphatidylinositols. 

Sharom, F.J., and Lehto, M.T., 2002, Glycosylphosphatidylinositol-anchored proteins Structure, function, and cleavage by phosphatidylinositol-specific phospholipase C. Biochem. Cell. Biol. 80 535-549. 

Glycosylphosphatidylinositol (GPI) membrane anchors constitute a class of glycolipids that covalently link certain proteins to cell and virion surfaces [122,123]. A boost in their chemistry occurred in 1988 when Ferguson et al. reported the first covalent structure of a member of this family [124,125]. The first synthesis of a fully phosphorylated GPI, compound 246 (O Fig. 5), was accomplished by Fraser-Reid s group based entirely on NPG chemistry [126,127,128,129,130]. 

Glycosylphosphatidylinositols are naturally occurring glycophospholipids on a cell surface. Full structural assignment was reported by Ferguson et al. in 1988 [142,143]. The core structure was composed of a carbohydrate residue with an ethanolamine side chain, inositol residue, and a phosphoglycerolipid residue (O Fig. 11). The carbohydrate residue, ethanolamine side chain or lipid moiety is species specific [144,145,146,147,148], and depends on species and... 

The core structures of glycosylphosphatidylinositol (GPI) anchors and the GPI anchoring of proteins and glycoproteins onto cell surfaces... 

J. O. Previato, C. Jones, L. P. B. Gonsalves, R. Wait, L. R. Travassos, A. J. Parodi, and L. Vlendonga-Previato, Structural characterization of the major glycosylphosphatidylinositol membrane-anchored glycoprotein from epimastigote forms of Trypanosoma cruzi Y-strain, J. Biol. Chem., 270 (1995) 7241-7250. 

R. Agusti, A. S. Couto, O. Campetella, A. C. C. Frasch, and R. M. de Lederkremer, Structure of the glycosylphosphatidylinositol-anchor of the frans-sialidase from Trypanosoma cruzi metacyclic trypomastigote forms, Mol. Biochem. Parasitol., 97 (1998) 123-131. 

A. S. Couto, R. M. de Lederkremer, W. Colli, and M. J. M. Alves, The glycosylphosphatidylinositol anchor of the trypomastigote specific Tc 85 glycoprotein from Trypanosoma cruzi. Metabolic labeling and structural studies, Eur. J. Biochem., 217 (1993) 597-602. 

M. L. Guther, M. L. de Almeida, N. Yoshida, and M. A. J. Ferguson, Structural studies on the glycosylphosphatidylinositol membrane anchor of Trypanosoma cruzi lG7-antigen. The structure of the glycan core,./. Biol. Chem., 267 (1992) 6820-6828. 

I. C. Almeida and R. T. Gazzinelli, Proinflammatory activity of glycosylphosphatidylinositol anchors derived from Trypanosoma cruzi. structural and functional analyses,. /. Leukoc. Biol., 70 (2001) 467-477. 

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