Spectroscopic evidence for amyloid-like interfacial self-assembly of hydrophobin Sc3

Amphipathic fungal proteins called hydrophobins are able to self-assemble i nto insoluble supramolecular structures at hydrophobic/hydrophilic interfac es, but the molecular mechanism and underlying protein conformation changes are not known. Secondary-structure prediction indicated that hydrophobin S c3 is an all-beta protein. Many amyloidogenic proteins self-assemble into i nsoluble amyloid fibrils while undergoing a change to an all-beta conformat ion. In this study we show that two dyes, thioflavin T, and Congo red, whic h are widely used for specific detection of stacked beta sheets, interact w ith Sc3 assemblies in the same way as with the amyloid beta -sheet fibrils. We conclude that Sc3, and probably other hydrophobins too, self-assemble a t interfaces in the same manner as amyloidogenic proteins, i.e., through be ta -sheet stacking. (C) 2001 Academic Press.