Influenza virus proton channels.

The M2 ion channel proteins of influenza A and B viruses are essential to viral replication. The two ion channels share a common motif, HXXXW, that is responsible for proton selectivity and activation. The ion channel for the influenza A virus, but not influenza B virus, is inhibited by the antiviral drug amantadine and amantadine-resistant escape mutants form in treated influenza A patients. The studies reviewed suggest that an antiviral compound directed against the conserved motif would be more useful than amantadine in inhibiting viral replication.