title: Interaction and comparison of a class I hydrophobin from Schizophyllum commune and class II hydrophobins from Trichoderma reesei.
abstract: Hydrophobins fulfill a wide spectrum of functions in fungal growth and development. These proteins self-assemble at hydrophilic-hydrophobic interfaces into amphipathic membranes. Hydrophobins are divided into two classes based on their hydropathy patterns and solubility. We show here that the properties of the class II hydrophobins HFBI and HFBII of Trichoderma reesei differ from those of the class I hydrophobin SC3 of Schizophyllum commune. In contrast to SC3, self-assembly of HFBI and HFBII at the water-air interface was neither accompanied by a change in secondary structure nor by a change in ultrastructure. Moreover, maximal lowering of the water surface tension was obtained instantly or took several minutes in the case of HFBII and HFBI, respectively. In contrast, it took several hours in the case of SC3. Oil emulsions prepared with HFBI and SC3 were more stable than those of HFBII, and HFBI and SC3 also interacted more strongly with the hydrophobic Teflon surface making it wettable. Yet, the HFBI coating did not resist treatment with hot detergent, while that of SC3 remained unaffected. Interaction of all the hydrophobins with Teflon was accompanied with a change in the circular dichroism spectra, indicating the formation of an alpha-helical structure. HFBI and HFBII did not affect self-assembly of the class I hydrophobin SC3 of S. commune and vice versa. However, precipitation of SC3 was reduced by the class II hydrophobins, indicating interaction between the assemblies of both classes of hydrophobins.
authors.affiliation: VTT Biotechnology, FI-02044 VTT, Finland, Biomade Technology, Nijenborgh 4, 9747 AG Groningen, The Netherlands. Sanna.Askolin@finnzymes.fi
authors.forename: Sanna
authors.initials: S
authors.lastname: Askolin
authors.forename: Markus
authors.initials: M
authors.lastname: Linder
authors.forename: Karin
authors.initials: K
authors.lastname: Scholtmeijer
authors.forename: Maija
authors.initials: M
authors.lastname: Tenkanen
authors.forename: Merja
authors.initials: M
authors.lastname: Penttilä
authors.forename: Marcel L
authors.initials: ML
authors.lastname: de Vocht
authors.forename: Han A B
authors.initials: HA
authors.lastname: Wösten
mesh_terms: D000388:Air; D001665:Binding Sites; D005656:Fungal Proteins / Q000737:chemistry* / Q000145:classification*; D057927:Hydrophobic and Hydrophilic Interactions; D009821:Oils / Q000737:chemistry; D012567:Schizophyllum / Q000737:chemistry*; D013499:Surface Properties; D014242:Trichoderma / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D005656:Fungal Proteins; D009821:Oils; D014867:Water