Fungal Hydrophobin Proteins Produce Self-Assembling Protein Films with Diverse Structure and Chemical Stability.
Hydrophobins are small proteins secreted by fungi and which spontaneously assemble into amphipathic layers at hydrophilic-hydrophobic interfaces. We have examined the self-assembly of the Class I hydrophobins EAS∆15and DewA, the Class II hydrophobin NC2 and an engineered chimeric hydrophobin. These Class I hydrophobins form layers composed of laterally associated fibrils with an underlying amyloid structure. These two Class I hydrophobins, despite showing significant conformational differences in solution, self-assemble to form fibrillar layers with very similar structures and require a hydrophilic-hydrophobic interface to trigger self-assembly. Addition of additives that influence surface tension can be used to manipulate the fine structure of the protein films. The Class II hydrophobin NC2 forms a mesh-like protein network and the engineered chimeric hydrophobin displays two multimeric forms, depending on assembly conditions. When formed on a graphite surface, the fibrillar EAS∆15layers are resistant to alcohol, acid and basic washes. In contrast, the NC2 Class II monolayers are dissociated by alcohol treatment but are relatively stable towards acid and base washes. The engineered chimeric Class I/II hydrophobin shows increased stability towards alcohol and acid and base washes. Self-assembled hydrophobin films may have extensive applications in biotechnology where biocompatible; amphipathic coatings facilitate the functionalization of nanomaterials.
Discipline of Pharmacology, School of Medical Sciences, The University of Sydney, Sydney NSW 2006, Australia. v.lo@usyd.edu.au.
Victor C
VC
Lo
Discipline of Pharmacology, School of Medical Sciences, The University of Sydney, Sydney NSW 2006, Australia. qren5387@uni.sydney.edu.au.
Qin
Q
Ren
Discipline of Pharmacology, School of Medical Sciences, The University of Sydney, Sydney NSW 2006, Australia. chi.pham@sydney.edu.au.
Chi L L
CL
Pham
Discipline of Pharmacology, School of Medical Sciences, The University of Sydney, Sydney NSW 2006, Australia. ann.kwan@sydney.edu.au.|School of Molecular Bioscience, The University of Sydney, Sydney NSW 2006, Australia. ann.kwan@sydney.edu.au.
Vanessa K
VK
Morris
School of Molecular Bioscience, The University of Sydney, Sydney NSW 2006, Australia. ann.kwan@sydney.edu.au.
Ann H
AH
Kwan
Discipline of Pharmacology, School of Medical Sciences, The University of Sydney, Sydney NSW 2006, Australia. margaret.sunde@sydney.edu.au.
Margaret
M
Sunde
amphipathic; film; hydrophobin; protein; self-assembly