Interaction of the N-terminal segment of HCV protein NS5A with model membranes.

We have identified a membrane-active region in the HCV NS5A protein by performing an exhaustive study of membrane rupture induced by a NS5A-derived peptide library on model membranes having different phospholipid compositions. We report the identification in NS5A of a highly membranotropic region located at the suggested membrane association domain of the protein. We report the binding and interaction with model membranes of two peptides patterned after this segment, peptides 1A and 1B, derived from the strains 1a_H77 and 1b_HC-4J respectively. We show that they insert into phospholipid membranes, interact with them, and are located in a shallow position in the membrane. The NS5A region where this segment resides might have an essential role in the membrane replication and/or assembly of the viral particle through the modulation of the replication complex, and consequently, directly implicated in the HCV life cycle.