orals 5th Asia-Pacific NMR Symposium 2013

Structural studies of the fibril-forming hydrophobins (#13)

Qin Ren 1 , Vanessa K Morris 1 , Anthony Rey 1 , Chi Le Lan Pham 1 , Ann H Kwan 1 , Margie Sunde 1
  1. University of Sydney, Sydney, NSW, Australia

Hydrophobins are small proteins found in all filamentous fungi that are able to self-assemble specifically at hydrophilic:hydrophobic interfaces to form highly ordered amphipathic monolayers. Some hydrophobins form monolayers that are composed of fibrils that share many of the structural characteristics of amyloid. For the fungus this amyloid layer is functional and plays important roles in the life-cycle, including mediating life at the air:water boundary and facilitating fungal:host interactions. We have determined the solution structures of a number of different hydrophobins in order to elucidate the key structural features that underpin the remarkable properties of these proteins1 . We have probed the process of self-assembly by hydrophobins using mutagenesis, in order to identify the conformational changes that occur upon fibril formation and the residues that form the ordered beta-sheet core of the fibrils2 . We have studied the role of the interface in triggering this protein assembly process. We have demonstrated that a threshold level of surface tension is necessary to trigger the conformational changes and intermolecular assembly which occur upon amyloid formation by hydrophobins. The amphipathic nature of the hydrophobin monolayers makes them attractive coatings for nanomaterials such as graphene that are otherwise incompatible with biological solutions. We have started a program of engineering hydrophobins to display functional groups and aim to exploit the self-assembly properties and the amphipathic nature of these proteins for synthesis of functional nanosurfaces.

  1. Morris, V. K., Kwan, A. H. & Sunde, M. (2012). Analysis of the Structure and Conformational States of DewA Gives Insight into the Assembly of the Fungal Hydrophobins. J Mol Biol. 425, 244-256.
  2. Macindoe, I., Kwan, A. H., Ren, Q., Morris, V. K., Yang, W., Mackay, J. P. & Sunde, M. (2012). Self-assembly of functional, amphipathic amyloid monolayers by the fungal hydrophobin EAS. Proc Natl Acad Sci U S A 2011-14052R.