Amantadine blocks channel activity of the transmembrane segment of the NB protein from influenza B

NB is short auxiliary protein with ca. 100 amino acids, encoded in the vira l genome of influenza B. It is believed to be similar to M2 from influenza A and Vpu from HIV-1 in that it demonstrates ion channel activity. Channels formed by the protein can be blocked by amantadine. We have synthesized th e putative transmembrane segment of NB (IRG S-20 IIITICVSL I-30 VILIVFGCI A (40) KIFI (NB, Lee)). Reconstituted in a lipid bilayer the peptide shows ch annel activity. The addition of amantadine leads to dose-dependent loss of channel activity. Channel blocking is reversible. Channel behaviour of the peptide in the presence of amantadine is in accordance with findings, for t he intact channel. Thus, the synthetic transmembrane peptide captures the i on channel activity of the intact NB protein.