Membrane interaction of segment H1 (NS4B(H1)) from hepatitis C virus non-structural protein 4B.

NS4B protein from hepatitis C virus (HCV) is a highly hydrophobic protein inducing a rearrangement of endoplasmic reticulum membranes responsible of the HCV replication process. Different helical elements have been found in the N- and C- terminal domains of the protein, which seem to be responsible for many key aspects of the viral replication process. In this work we have carried out a study of the binding and interaction with model biomembranes of peptide NS4B(H1), patterned after segment H1, one of these C-terminal previously identified segments. We show that NS4B(H1) partitions into phospholipid membranes; its membrane activity is modulated by lipid composition, interacting preferentially with negatively charged phospholipids as well as with sphingomyelin. Furthermore, the change in its sequence prevents the resulting peptide from interacting with the membrane. These data would support its role in the interaction of NS4B with the membrane and suggest that the region where this peptide resides could be involved in the membrane alteration which must occur in the HCV replication and/or assembly process.