Lebedev, D. V. | bioRxiv Science

bioRxiv2018

Changing Times: Fluorescence-lifetime Analysis of Amyloidogenic SF-IAPP Fusion Protein

The fluorescence lifetime of the superfolder green fluorescent protein (SF) and the SF protein fused with islet amyloid polypeptide (SF-IAPP) were studied in polyacrylamide gel. It was shown that the SF average fluorescence lifetime under these conditions slightly differs from that of the SF-IAPP monomer. SF-IAPP does not lose the ability to form amyloid-like fibrils; meanwhile, the average fluorescence lifetime of the fusion protein in fibrils is reduced. We propose the application of Fluorescent-lifetime Imaging Microscopy (FLIM) to the measurement of average fluorescence lifetimes of fusion proteins (amyloidogenic protein-SF) in the context of studies using cellular models of conformational diseases.

biophysics↗

bioRxiv2017

The amyloidogenicity of the influenza virus PB1-derived peptide sheds light on its antiviral activity

The influenza virus polymerase complex is a promising target for new antiviral drug development. It is known that, within the influenza virus polymerase complex, the PB1 subunit region from the 1st to the 25th amino acid residues has to be is in an alpha-helical conformation for proper interaction with the PA subunit. We have previously shown that PB1(6-13) peptide at low concentrations is able to interact with the PB1 subunit N-terminal region in a peptide model which shows aggregate formation and antiviral activity in cell cultures.\n\nIn this paper, it was shown that PB1(6-13) peptide is prone to form the amyloid-like fibrillar aggregates. The peptide homo-oligomerization kinetics were examined, and the affinity and characteristic interaction time of PB1(6-13) peptide monomers and the influenza virus polymerase complex PB1 subunit N-terminal region were evaluated by the SPR and TR-SAXS methods. Based on the data obtained, a hypothesis about the PB1(6-13) peptide mechanism of action was proposed: the peptide in its monomeric form is capable of altering the conformation of the PB1 subunit N-terminal region, causing a change from an alpha helix to a beta structure. This conformational change disrupts PB1 and PA subunit interaction and, by that mechanism, the peptide displays antiviral activity.\n\nGraphical abstract\n\nO_FIG O_LINKSMALLFIG WIDTH=199 HEIGHT=200 SRC=\"FIGDIR/small/211284_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (77K):\norg.highwire.dtl.DTLVardef@185db47org.highwire.dtl.DTLVardef@ff2fd2org.highwire.dtl.DTLVardef@19c8587org.highwire.dtl.DTLVardef@10282b1_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗