Glycosylinositolphosphoceramides in Aspergillus fumigatus
Catherine Simenel1, Bernadette Coddeville, Muriel Delepierre
1Unité de Résonance Magnétique Nucléaire des Biomolécules, CNRS URA 2185 Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris cedex 15, France.
Abstract:
Fungal glycosylinositolphosphoceramides (GIPCs) are involved in cell growth and fungal-host interactions. In this study, six GIPCs from the mycelium of the human pathogen Aspergillus fumigatus were purified and characterized using Q-TOF mass spectrometry and 1H, 13C, and 31P NMR. All structures have the same inositolphosphoceramide moiety with the presence of a C(18:0)-phytosphingosine conjugated to a 2-hydroxylated saturated fatty acid (2-hydroxy-lignoceric acid). The carbohydrate moiety defines two types of GIPC. The first, a mannosylated zwitterionic glycosphingolipid contains a glucosamine residue linked in alpha1-2 to an inositol ring that has been described in only two other fungal pathogens. The second type of GIPC presents an alpha-Manp-(1-->3)-alpha-Manp-(1-->2)-IPC common core. A galactofuranose residue is found in four GIPC structures, mainly at the terminal position via a beta1-2 linkage. Interestingly, this galactofuranose residue could be substituted by a choline-phosphate group, as observed only in the GIPC of Acremonium sp., a plant pathogen.
Insights
Six fungal glycosylinositolphosphoceramides (GIPCs) from Aspergillus fumigatus were identified. These GIPCs, crucial for fungal growth and host interactions, exhibit unique structural variations impacting their function.
Area of Science:
- Mycology
- Biochemistry
- Glycobiology
Background:
- Fungal glycosylinositolphosphoceramides (GIPCs) are essential components of fungal cell membranes.
- They play critical roles in fungal growth, development, and interactions with host organisms.
- Understanding GIPC structure is key to deciphering their biological functions.
Purpose of the Study:
- To purify and characterize novel GIPCs from the human pathogen Aspergillus fumigatus.
- To elucidate the structural diversity of GIPCs in Aspergillus fumigatus.
- To compare the identified GIPCs with those found in other fungal pathogens.
Main Methods:
- Purification of six GIPCs from Aspergillus fumigatus mycelium.
- Structural characterization using Q-TOF mass spectrometry.
- Detailed structural analysis via 1H, 13C, and 31P Nuclear Magnetic Resonance (NMR) spectroscopy.
Main Results:
- All identified GIPCs share a common inositolphosphoceramide moiety with C(18:0)-phytosphingosine and 2-hydroxy-lignoceric acid.
- Two distinct types of GIPC carbohydrate moieties were identified.
- Four GIPCs contained a galactofuranose residue, sometimes substituted with a choline-phosphate group.
Conclusions:
- The study reveals significant structural diversity in GIPCs from Aspergillus fumigatus.
- The identified GIPCs, particularly the mannosylated zwitterionic glycosphingolipid and the galactofuranose-containing structures, offer insights into fungal-host interactions.
- The findings contribute to the understanding of GIPC roles in fungal pathogens and their potential as therapeutic targets.
