PB1-F2 Influenza A Virus Protein Adopts a beta-Sheet Conformation and Forms Amyloid Fibers in Membrane Environments - INRAE - Institut national de recherche pour l’agriculture, l’alimentation et l’environnement Access content directly
Journal Articles Journal of Biological Chemistry Year : 2010

PB1-F2 Influenza A Virus Protein Adopts a beta-Sheet Conformation and Forms Amyloid Fibers in Membrane Environments

Abstract

The influenza A virus PB1-F2 protein, encoded by an alternative reading frame in the PB1 polymerase gene, displays a high sequence polymorphism and is reported to contribute to viral pathogenesis in a sequence-specific manner. To gain insights into the functions of PB1-F2, the molecular structure of several PB1-F2 variants produced in Escherichia coli was investigated in different environments. Circular dichroism spectroscopy shows that all variants have a random coil secondary structure in aqueous solution. When incubated in trifluoroethanol polar solvent, all PB1-F2 variants adopt an _-helix-rich structure, whereas incubated in acetonitrile, a solvent of medium polarity mimicking the membrane environment, they display_-sheet secondary structures. Incubated with asolectin liposomes and SDS micelles, PB1-F2 variants also acquire a _-sheet structure. Dynamic light scattering revealed that the presence of_-sheets is correlated with an oligomerization/aggregation of PB1-F2. Electron microscopy showed that PB1-F2 forms amorphous aggregates in acetonitrile. In contrast, at low concentrations of SDS, PB1-F2 variants exhibited various abilities to form fibers that were evidenced as amyloid fibers in a thioflavin T assay. Using a recombinant virus and its PB1-F2 knock-out mutant, we show that PB1-F2 also forms amyloid structures in infected cells. Functional membrane permeabilization assays revealed that the PB1-F2 variants can perforatemembranes at nanomolar concentrations but with activities found to be sequence-dependent and not obviously correlated with their differential ability to form amyloid fibers. All of these observations suggest that PB1-F2 could be involved in physiological processes through different pathways, permeabilization of cellular membranes, and amyloid fiber formation.
Fichier principal
Vignette du fichier
2010_Chevalier_Journal of Biological Chemistry_1.pdf (3.19 Mo) Télécharger le fichier
Origin : Publisher files allowed on an open archive
Loading...

Dates and versions

hal-02664783 , version 1 (31-05-2020)

Licence

Copyright

Identifiers

Cite

Christophe Chevalier, Ali Al Bazzal, Jasmina Vidic, Vincent Fevrier, Christiane Bourdieu, et al.. PB1-F2 Influenza A Virus Protein Adopts a beta-Sheet Conformation and Forms Amyloid Fibers in Membrane Environments. Journal of Biological Chemistry, 2010, 285 (17), pp.13233-13243. ⟨10.1074/jbc.M109.067710⟩. ⟨hal-02664783⟩
42 View
60 Download

Altmetric

Share

Gmail Facebook X LinkedIn More