Interaction between the NS4B amphipathic helix, AH2, and charged lipid headgroups alters membrane morphology and AH2 oligomeric state — Implications for the Hepatitis C virus life cycle

Abstract

The non-structural protein 4B (NS4B) from Hepatitis C virus (HCV) plays a pivotal role in the remodelling of the host cell's membranes, required for the formation of the viral replication complex where genome synthesis occurs. NS4B is an integral membrane protein that possesses a number of domains vital for viral replication. Structural and biophysical studies have revealed that one of these, the second amphipathic N-terminal helix (AH2), plays a key role in these remodelling events. However, there is still limited understanding of the mechanism through which AH2 promotes these changes. Here we report on solid-state NMR and molecular dynamics studies that demonstrate that AH2 promotes the clustering of negatively charged lipids within the bilayer, a process that reduces the strain within the bilayer facilitating the remodelling of the lipid bilayer. Furthermore, the presence of negatively charged lipids within the bilayer appears to promote the disassociation of AH2 oligomers, highlighting a potential role for lipid recruitment in regulating NS protein interactions.

Structural Ensembles of Membrane-bound α-Synuclein Reveal the Molecular Determinants of Synaptic Vesicle Affinity

“…Electrostatic interactions between M1, K6, K10 and K12 and the charged groups of the lipids are also observed, evidencing a stabilising factor for the membrane binding by the N-terminal region of αS 1-30 (Fig. 3c), which represents a consistent key factor within different membrane binding systems404142. Overall these data indicate that the initial 12 residues of the protein sequence enable αS to establish tight interactions with the membrane, including the internal hydrophobic region of the lipid bilayer.…”

C60fullerene localization and membrane interactions in RAW 264.7 immortalized mouse macrophages

“…Furthermore, the observed changes in the distribution of intensity in the 31 P spectrum reflect differences in the orientational distribution of the lipids within the sample 48,55–57 with an increase in intensity in the low-field region corresponding to an enhanced probability of lipids aligning with their long axis parallel to the magnetic field. On the contrary, typical static 31 P NMR spectra of lipid vesicles exhibit a reduced intensity in the low-field region due to the preferred orientation of lipids with their long axes perpendicular to the applied magnetic field, arising from their intrinsic diamagnetic anisotropy.…”

Emerging Diversity in Lipid–Protein Interactions

“…The structural characteristics, molecular assembly and ion conductivity of Hepatitis virus proteins in various lipid compositions have also been studied by means of MD simulations. 738−740 The Hepatitis C virus p7 viroporin is a potential drug target that controls the permeability of the membrane to ions and facilitates virus production, analogous to M2 from influenza A virus. Chandler et al used monomeric p7 to build oligomeric models with 4 to 7 subunits in hydrated POPC lipid bilayers.…”