The cell wall of the human opportunistic pathogen is a complex structure mainly composed of polysaccharides, β (1-3) glucan being the most abundant. In a way similar to other fungi, β (1-3) glucan of A. fumigatus serve as a skeleton on which the other polysaccharides of the cell wall (chitin and galactomannan) become anchored. A new β (1-3) glucanosyltransferase (Gel1p) isolated from the cell wall of A. fumigatus has been discovered and characterised. This enzyme splits internally a β (1-3) glucan molecule and transfers the newly generated reducing end to the non reducing end of another β (1-3) glucan molecule. The creation of a new β (1-3) glucan resulted in the elongation of β (1-3) glucan chains. Gel1p belongs to a family of seven members, which are GPI anchored protein. Only Gel1p, Gel2p and Gel4p are expressed in normal growth conditions. An analysis of these 3 proteins using biochemical and molecular method is presented here. GEL1 deletion has no phenotype but disruption of GEL2 gene results in alteration of polar growth, reduced growth, abnormal conidiophores and a decrease in virulence. All attempt to disrupt GEL4 have been unsuccessful to date this results suggest that GEL4 is essential for A. fumigatus. The enzymatic activity of Gel4p is being investigated using a recombinant protein produced in Pichia pastoris.
Full conference title:
The First International Fungal / Plant Cell Wall Meeting
- International Fungal / Plant Cell Wall Meeting 1st