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 Ca2+ ions. A model of self-assembly into amyloid-like structures has been proposed.

Class i Hydrophobin Vmh2 Adopts Atypical Mechanisms to Self-Assemble into Functional Amyloid Fibrils

GRAVAGNUOLO, ALFREDO MARIA;LONGOBARDI, SARA;LUCHINI, ALESSANDRA;DE STEFANO, Luca;NOTOMISTA, EUGENIO;PADUANO, LUIGI;GIARDINA, PAOLA
2016

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 Ca2+ ions. A model of self-assembly into amyloid-like structures has been proposed.
File in questo prodotto:
File Dimensione Formato  
Class I Hydrophobin Vmh2 Adopts Atypical Mechanisms to Self-Assemble into Functional Amyloid Fibrils.pdf

non disponibili

Descrizione: Articolo principale
Tipologia: Versione Editoriale (PDF)
Licenza: Accesso privato/ristretto
Dimensione 2.13 MB
Formato Adobe PDF
2.13 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Class I Hydrophobin Vmh2 Adopts Atypical Mechanisms to Self-Assemble into Functional Amyloid Fibrils_SI.pdf

accesso aperto

Descrizione: Materiale supplementare
Tipologia: Altro materiale allegato
Licenza: Dominio pubblico
Dimensione 913.14 kB
Formato Adobe PDF
913.14 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/635987
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 26
  • ???jsp.display-item.citation.isi??? 24
social impact