Hydrophobin

Hydrophobins are a group of small (~100 amino acids) cysteine-rich proteins that are expressed only by filamentous fungi. They are known for their ability to form a hydrophobic (water-repellent) coating on the surface of an object. They were first discovered and separated in Schizophyllum commune in 1991. Based on differences in hydropathy patterns and biophysical properties, they can be divided into two categories: class I and class II. Hydrophobins can self-assemble into a monolayer on hydrophobic:hydrophilic interfaces such as a water:air interface. Class I monolayer contains the same core structure as amyloid fibrils, and is positive to Congo red and thioflavin T. The monolayer formed by class I hydrophobins has a highly ordered structure, and can only be dissociated by concentrated trifluoroacetate or formic acid. Monolayer assembly involves large structural rearrangements with respect to the monomer.