MYSFVSEET GTLIVNSVLLFLAFVVFLLVTLAILTAL RLAAYAANIVNVSLVKP T V YVYSRVKNL ). Left, side view with hexamethylene amiloride ligand in the pore (gray). Right, axial view from the N-terminus. Green cage, the docking site. Probably the most widely known drug acting as a viroporin blocker is amantadine (aminoadamantane), which has been in the medical practice to treat influenza since 1966, even before the viral ion channels were discovered. It blocks the M2 channel of influenza A virus and inhibits its replication . The binding of amantadine to a synthetic TMD of E protein from SARS-CoV (sequence KKTGTLIVNSVLLFLAFVVFLLVTLAILTKK) was significant enough (K d 7 mM) to completely block the ion conductance .