title: Probing the self-assembly and the accompanying structural changes of hydrophobin SC3 on a hydrophobic surface by mass spectrometry.
abstract: The fungal class I hydrophobin SC3 self-assembles into an amphipathic membrane at hydrophilic-hydrophobic interfaces such as the water-air and water-Teflon interface. During self-assembly, the water-soluble state of SC3 proceeds via the intermediate alpha-helical state to the stable end form called the beta-sheet state. Self-assembly of the hydrophobin at the Teflon surface is arrested in the alpha-helical state. The beta-sheet state can be induced at elevated temperature in the presence of detergent. The structural changes of SC3 were monitored by various mass spectrometry techniques. We show that the so-called second loop of SC3 (C39-S72) has a high affinity for Teflon. Binding of this part of SC3 to Teflon was accompanied by the formation of alpha-helical structure and resulted in low solvent accessibility. The solvent-protected region of the second loop extended upon conversion to the beta-sheet state. In contrast, the C-terminal part of SC3 became more exposed to the solvent. The results indicate that the second loop of class I hydrophobins plays a pivotal role in self-assembly at the hydrophilic-hydrophobic interface. Of interest, this loop is much smaller in case of class II hydrophobins, which may explain the differences in their assembly.
authors.affiliation: Department of Biochemistry and Mass Spectrometry Core Facility, University of Groningen, Groningen, The Netherlands.
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.forename: H P
authors.initials: HP
authors.lastname: Permentier
authors.forename: R
authors.initials: R
authors.lastname: Rink
authors.forename: J A W
authors.initials: JA
authors.lastname: Kruijtzer
authors.forename: R M J
authors.initials: RM
authors.lastname: Liskamp
authors.forename: H A B
authors.initials: HA
authors.lastname: Wösten
authors.forename: B
authors.initials: B
authors.lastname: Poolman
authors.forename: G T
authors.initials: GT
authors.lastname: Robillard
mesh_terms: D000388:Air; D000595:Amino Acid Sequence; D002942:Circular Dichroism; D003902:Detergents / Q000494:pharmacology; D010450:Endopeptidases / Q000494:pharmacology; D005561:Formates / Q000737:chemistry; D005656:Fungal Proteins / Q000737:chemistry*; D007700:Kinetics; D013058:Mass Spectrometry / Q000379:methods*; D008666:Metalloendopeptidases; D008969:Molecular Sequence Data; D010100:Oxygen / Q000378:metabolism; D010434:Pepsin A / Q000494:pharmacology; D010455:Peptides / Q000737:chemistry; D011138:Polytetrafluoroethylene / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013696:Temperature; D013997:Time Factors; D014867:Water
chemical_list: D003902:Detergents; D005561:Formates; D005656:Fungal Proteins; D010455:Peptides; D014867:Water; C008817:peroxyformic acid; D011138:Polytetrafluoroethylene; D010450:Endopeptidases; D010434:Pepsin A; D008666:Metalloendopeptidases; C058921:endoproteinase Asp-N; D010100:Oxygen