Table II. Mucin- and GIPL-derived GPIs isolated from different strains of T.cruzi epimastigotes.
| Epimastigote strain | GPI origina | Major ion speciesb [M-2H]2– | Molecular mass (Da) | Proposed assignment for the GPI |
|
|---|---|---|---|---|---|
| Glycan core | Lipid component of the PI moiety | ||||
| Y | GIPLs | 1038.3 | 2078.6 | [Hex5-GlcN][AEP]2 | CER, (C24:0)fatty acid-(C18:0)sphinganine |
| 1046.5 | 2095.0 | [Hex5-GlcN][EtNP][AEP] | CER, (C24:0)fatty acid-(C18:0)sphinganine | ||
| 1065.6 | 2133.2 | [Hex6-GlcN][AEP] | CER, (C24:0)fatty acid-(C18:0)sphinganine | ||
| mucins | 908.9 | 1819.8 | [Hex4-GlcN][AEP]2 | AAG, (C16:0)alkyl-(C16:0)acylglycerol | |
| 916.8 | 1835.6 | [Hex4-GlcN][EtNP][AEP] | AAG, (C16:0)alkyl-(C16:0)acylglycerol | ||
| 997.9 | 1997.8 | [Hex5-GlcN][EtNP][AEP] | AAG, (C16:0)alkyl-(C16:0)acylglycerol | ||
| CL | GIPLs | 989.8 | 1981.6 | [Hex5-GlcN][AEP]2 | AAG, (C16:0)alkyl-(C16:0)acylglycerol |
| 997.8 | 1997.6 | [Hex5-GlcN][EtNP][AEP] | AAG, (C16:0)alkyl-(C16:0)acylglycerol | ||
| 1017.1 | 2036.2 | [Hex6-GlcN][AEP] | AAG, (C16:0)alkyl-(C16:0)acylglycerol | ||
| 1038.3 | 2078.6 | [Hex5-GlcN][AEP]2 | CER, (C24:0)fatty acid-(C18:0)sphinganine | ||
| 1046.5 | 2095.0 | [Hex5-GlcN][EtNP][AEP] | CER, (C24:0)fatty acid-(C18:0)sphinganine | ||
| 1065.6 | 2133.2 | [Hex6-GlcN][AEP] | CER, (C24:0)fatty acid-(C18:0)sphinganine | ||
| mucins | 789.8c | 1581.6 | [Hex4-GlcN][AEP]2 | MAG, (C16:0)mono(lyso)alkyl-glycerol | |
| 797.8c | 1597.6 | [Hex4-GlcN][EtNP][AEP] | MAG, (C16:0)mono(lyso)alkyl-glycerol | ||
| Tulahuen | GIPLs | 908.9 | 1819.8 | [Hex4-GlcN][AEP]2 | AAG, (C16:0)alkyl-(C16:0)acylglycerol |
| 965.2 | 1932.4 | [Hex4-GlcN][EtNP][AEP] | CER, (C24:0)fatty acid-(C18:0)sphinganine | ||
| mucins | 916.8 | 1835.6 | [Hex4-GlcN][EtNP][AEP] | AAG, (C16:0)alkyl-(C16:0)acylglycerol | |
aThe GPI anchor was obtained after proteinase K digestion of the purified mucin as described in Materials and methods.
bThe most abundant GPI species within the mixture is underlined.
cThe monoalkyglycerol-PI species was obtained from alkylacylglycerol-PI (m/z 909 or 917) species after alkaline hydrolysis (6 M ammonium hydroxide, 37°C, 1 h), to remove the fatty acid at the sn-2 position of the glycerol, followed by purification on an octyl-Sepharose column.
CER, ceramide; AAG, alkylacylglycerol; MAG, monoalkylglycerol.