The tetrameric influenza B M2 channel(BM2),an acid activated proton channel,is important in the influenza virus B lifecycle.A conserved HxxxW motif is responsible for proton conduction and channel gating.In this study,to explore the effects of the serine triad(S9,S12 and S16) on proton conduction,we performed classical molecular dynamics(CMD) simulations and adaptive steered molecular dynamics(ASMD) simulations at different protonation states of the H19 tetrad.