Dr Margaret Sunde
D06 - Blackburn Building
The formation of stable, fibrillar protein assemblies is associated with many disease states, including Alzheimer's disease and Type II diabetes. These are non-functional deposits. Protein aggregates that have similar structural features but which are functional have been identified in several microorganisms. In these cases the self-assembly of the protein is advantageous to the organism. For example, hydrophobins are fungal proteins that self-assemble in an ordered manner into amphipathic films at air:water interfaces. They reduce the surface tension at air:water boundaries and form very hydrophobic coatings on fungal spore surfaces which facilitate dispersal in air. Hydrophobin assemblies share the ordered beta-sheet structural core that has been characterized in amyloid deposits.
Hydrophobin assemblies shield the human pathogenic fungus Aspergillus fumigatus from the immune response during infection, allowing this fungus to go on to cause life-threatening invasive aspergillosis. In rice blast, the most important fungal disease of rice, infection of the plants is facilitated by the production of a hydrophobin layer by the fungus Magnaporthe grisea. We are therefore interested in studying the biophysical and structural basis for the self-assembly of hydrophobins, with a view to understanding the role played by these proteins in fungal infections.
Hydrophobin monolayer formation is a unique system that combines protein self-assembly with the generation of functional surfaces. These remarkable properties suggest a range of commercial applications, including biocompatibility enhancement of medical implants and emulsion and dispersion applications in foods and pharmaceuticals. This project involves using mutagenesis to probe the effect of sequence on hydrophobin structure and the study of the self-assembly process with techniques such as fluorescence, nuclear magnetic resonance, X-ray fibre diffraction and electron microscopy. Our work aims to develop a detailed picture of hydrophobin organisation within surface films. We hope to manipulate the self-assembly properties of the hydrophobins for the rational design of novel biological polymers and to design molecules that inhibit fungal spore dispersal and colonisation.
Current national competitive grants*
Breaching the defences: the role of hydrophobin protein monolayers in rice blast fungal infections
Sunde M, Kwan A
ARC Discovery Projects ($290,000 over 3 years)
* Grants administered through the University of Sydney