The influenza m2 cytoplasmic tail changes the proton-exchange equilibria and the backbone conformation of the transmembrane histidine residue to facilitate proton conduction.

ABSTRACT: The influenza M2 protein forms an acid-activated tetrameric proton channel important for the virus lifecycle. Residue His37 in the transmembrane domain is responsible for channel activation and proton selectivity. While the structure and dynamics of His37 have been well studied in TM peptide constructs, it has not been investigated in the presence of the full cytoplasmic domain, which increases the proton conductivity by 2-fold compared to the TM peptide. We report here (13)C and (15)N chemical shifts of His37 in the cytoplasmic-containing M2(21-97) and show that cationic histidines are already present at neutral pH, in contrast to the TM peptide, indicating that the cytoplasmic domain shifts the protonation equilibria. Quantification of the imidazole (15)N intensities yielded two resolved

SUBMITTER: Liao SY 

PROVIDER: S-EPMC4554341 | biostudies-literature | 2015 May

REPOSITORIES: biostudies-literature