Interaction of short modified peptides deriving from glycoprotein gp36 of feline immunodeficiency virus with phospholipid membranes

A tryptophan-rich octapeptide, C8 (Ac-Trp-Glu-Asp-Trp-Val-Gly-Trp-Ile-NH2), modelled on the membrane-proximal external region of the feline immunodeficiency virus (FIV) gp36 glycoprotein ectodomain, exhibits potent antiviral activity against FIV. A mechanism has been proposed by which the peptide, being positioned on the surface of the cell membrane, inhibits its fusion with the virus. In the present work, peptide–lipid interactions of C8 with dimyristoyl phosphatidylcholine liposomes are investigated using electron spin resonance spectroscopy of spin-labelled lipids. Three other peptides, obtained from modifications of C8, have also been investigated, in an attempt to clarify the essential molecular features of the interactions involving the tryptophan residues. The results show that C8 adsorbs strongly on the bilayer surface. Membrane binding requires not only the presence of the Trp residues in the sequence, but also their common orientation on one side of the peptide that is engendered by the WX2 WX2 W motif. Membrane interaction correlates closely with peptide antiviral activity, indicating that the membrane is essential in stabilizing the peptide conformation that will be able to inhibit viral infection

A General Strategy to Endow Natural Fusion-protein-Derived Peptides with Potent Antiviral Activity

Fusion between the viral and target cell membranes is an obligatory step for the infectivity of all enveloped virus, and blocking this process is a clinically validated therapeutic strategy

Genome Sequence of Rhodococcus opacus Strain R7, a Biodegrader of Mono- and Polycyclic Aromatic Hydrocarbons

Rhodococcus opacus strain R7 (CIP107348) degrades several mono- and polycyclic aromatic hydrocarbons. Here, we present the high-quality draft genome sequence of strain R7, consisting of 10,118,052 bp, with a G+C content of 67.0%, 9,602 protein-coding genes, and 62 RNAs genes

Exploring interaction of β-amyloid segment (25–35) with membrane models through paramagnetic probes

The accumulation of β-amyloid peptides into senile plaques is one of the hallmarks of Alzheimer’s disease (AD). There is mounting evidence that the lipid matrix of neuronal cell membranes plays an important role in the β-sheet oligomerization process of β-amyloid. Aβ(25–35), the sequence of which is GSNKGAIIGLM, is a highly toxic segment of amyloid β (Aβ)-peptides, which forms fibrillary aggregates. In the present work, two spin-labelled Aβ(25–35) analogues containing the nitroxide group of the amino acid TOAC (2,2,6,6-tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid) as a paramagnetic probe at the N- or the C-terminus of the peptide sequence, respectively, were synthesized in order to investigate the peptide-membrane interaction. The orientation and associated changes of the peptide conformation in the presence of different artificial membrane models (micelles, liposomes) were evaluated by electron paramagnetic resonance and circular dichroism techniques. The results of this study allowed us to propose a model in which the C-terminal portion of the peptide is highly associated to the membrane, while the N-terminal part extends into the aqueous phase with occasional contacts with the lipid head-group region. Interestingly, the interaction of the C-terminal portion of the peptide is particularly enhanced in the presence of sodium dodecyl sulfate (SDS) molecules