Influenza A M2 transmembrane domain tunes its conformational heterogeneity and structural plasticity in the lipid bilayer by forming loop structures.

We discovered for the first time that the influenza A virus M2TM tunes its conformational heterogeneity and structural plasticity to respond to environmental cues by undergoing a helix-to-loop transition, resolving controversies regarding the mechanism of proton conduction and plasticity of the M2TM in lipid bilayers.