ION-CHANNEL ACTIVITY OF INFLUENZA-A VIRUS M(2) PROTEIN - CHARACTERIZATION OF THE AMANTADINE BLOCK

The influenza A virus M2 integral membrane protein has ion channel act ivity which can be blocked by the antiviral drug amantadine. The M2 pr otein transmembrane domain is highly conserved in amino acid sequence for all the human, swine, equine, and avian strains of influenza A vir us, and thus, known amino acid differences could lead to altered prope rties of the M2 ion channel. We have expressed in oocytes of Xenopus l aevis the M2 protein of human influenza virus A/Udorn/72 and the avian virus A/chicken/Germany/34 (fowl plague virus, Rostock) and derivativ es of the Rostock ion channel altered in the presumed pore region. The pH of activation of the M2 ion channels and amantadine block of the M 2 ion channels were investigated. The channels were found to be activa ted by pH in a similar manner but differed in their apparent K(i)s for amantadine block.