Structures of the glycosylphosphatidylinositol membrane anchors from Aspergillus fumigatus membrane proteins
Glycosylphosphatidylinositol (GPI)-anchored proteins have been identified in all eukaryotes. In fungi, structural and biosynthetic studies of GPIs have been restricted to the yeast Saccharomyces cerevisiae. In this article, four GPI-anchored proteins were purified from a membrane preparation of the...
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Published in: | Glycobiology (Oxford) 2003-03, Vol.13 (3), p.169-177 |
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Main Authors: | , , , , , |
Format: | Article |
Language: | eng |
Subjects: | |
Online Access: | Get full text |
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Summary: | Glycosylphosphatidylinositol (GPI)-anchored proteins have been identified in all eukaryotes. In fungi, structural and biosynthetic studies of GPIs have been restricted to the yeast Saccharomyces cerevisiae. In this article, four GPI-anchored proteins were purified from a membrane preparation of the human filamentous fungal pathogen Aspergillus fumigatus. Using new methodology applied to western blot protein bands, the GPI structures were characterized by ES-MS, fluorescence labeling, HPLC, and specific enzymatic digestions. The phosphatidylinositol moiety of the A. fumigatus GPI membrane anchors was shown to be an inositol-phosphoceramide containing mainly phytosphingosine and monohydroxylated C24:0 fatty acid. In constrast to yeast, only ceramide was found in the GPI anchor structures of A. fumigatus, even for Gel1p, a homolog of Gas1p in S. cerevisiae that contains diacylglycerol. The A. fumigatus GPI glycan moiety is mainly a linear pentomannose structure linked to a glucosamine residue: Manα1-3Manα1-2Manα1-2Manα1-6Manα1-4GlcN. |
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ISSN: | 0959-6658 1460-2423 1460-2423 |