| Autor: |
Gravagnuolo AM; Department of Chemical Sciences, University of Naples 'Federico II' , Via Cintia 4, 80126 Naples, Italy., Longobardi S; Department of Chemical Sciences, University of Naples 'Federico II' , Via Cintia 4, 80126 Naples, Italy., Luchini A; Department of Chemical Sciences, University of Naples 'Federico II' , Via Cintia 4, 80126 Naples, Italy., Appavou MS; Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, Lichtenbergstraße 1, 85747 Garching, Germany., De Stefano L; Unit of Naples, Institute for Microelectronics and Microsystems, National Council of Research, Via Pietro Castellino 111, 80131 Naples, Italy., Notomista E; Department of Biology, University of Naples 'Federico II' , Via Cintia 4, 80126 Naples, Italy., Paduano L; Department of Chemical Sciences, University of Naples 'Federico II' , Via Cintia 4, 80126 Naples, Italy., Giardina P; Department of Chemical Sciences, University of Naples 'Federico II' , Via Cintia 4, 80126 Naples, Italy. |
| Abstrakt: |
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. |
