title: Class I Hydrophobin Vmh2 Adopts Atypical Mechanisms to Self-Assemble into Functional Amyloid Fibrils.
abstract: Hydrophobins are fungal proteins whose functions are mainly based on their capability to self-assemble into amphiphilic films at hydrophobic-hydrophilic interfaces (HHI). It is widely accepted that class I hydrophobins form amyloid-like structures, named rodlets, which are hundreds of nanometers long, packed into ordered lateral assemblies and do not exhibit an overall helical structure. We studied the self-assembly of the Class I hydrophobin Vmh2 from Pleurotus ostreatus in aqueous solutions by dynamic light scattering (DLS), thioflavin T (ThT), fluorescence assay, circular dichroism (CD), cryogenic trasmission electron microscopy (cryo-TEM), and TEM. Vmh2 does not form fibrillar aggregates at HHI. It exhibits spherical and fibrillar assemblies whose ratio depends on the protein concentration when freshly solubilized at pH ≥ 7. Moreover, it spontaneously self-assembles into isolated, micrometer long, and twisted amyloid fibrils, observed for the first time in fungal hydrophobins. This process is promoted by acidic pH, temperature, and Ca(2+) ions. A model of self-assembly into amyloid-like structures has been proposed.
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II" , Via Cintia 4, 80126 Naples, Italy.
authors.forename: Alfredo Maria
authors.initials: AM
authors.lastname: Gravagnuolo
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II" , Via Cintia 4, 80126 Naples, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Longobardi
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II" , Via Cintia 4, 80126 Naples, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Luchini
authors.affiliation: Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, Lichtenbergstraße 1, 85747 Garching, Germany.
authors.forename: Marie-Sousai
authors.initials: MS
authors.lastname: Appavou
authors.affiliation: Unit of Naples, Institute for Microelectronics and Microsystems, National Council of Research, Via Pietro Castellino 111, 80131 Naples, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: De Stefano
authors.affiliation: Department of Biology, University of Naples "Federico II" , Via Cintia 4, 80126 Naples, Italy.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Notomista
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II" , Via Cintia 4, 80126 Naples, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Paduano
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II" , Via Cintia 4, 80126 Naples, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Giardina
mesh_terms: D000682:Amyloid / Q000737:chemistry* / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry* / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D020076:Pleurotus / Q000737:chemistry; D011485:Protein Binding
chemical_list: D000682:Amyloid; D005656:Fungal Proteins