EPR Spectroscopy of the C-terminal Domain of the M2 Protein from Influenza A Virus

Abstract

The M2 protein from influenza A is a pH-activated proton channel that plays an essential role in the viral life cycle and serves as a drug target. Using spin labeling EPR spectroscopy we studied a 38-residue M2 peptide spanning the transmembrane region and its C-terminal extension. We obtained residue-specific environmental parameters under both high and low pH conditions for eleven consecutive C-terminal sites. We have also collected data in the presence of the antiviral drugs amantadine and rimantadine. The C-terminal region forms a membrane surface helix at both high and low pH although the arrangement of the monomers within the tetramer changes with pH and drug binding.