title: pH-induced conformational change of the influenza M2 protein C-terminal domain.
abstract: The M2 protein from influenza A is a pH-activated proton channel that plays an essential role in the viral life cycle and serves as a drug target. Using spin labeling EPR spectroscopy, we studied a 38-residue M2 peptide spanning the transmembrane region and its C-terminal extension. We obtained residue-specific environmental parameters under both high- and low-pH conditions for nine consecutive C-terminal sites. The region forms a membrane surface helix at both high and low pH, although the arrangement of the monomers within the tetramer changes with pH. Both electrophysiology and EPR data point to a critical role for residue Lys 49.
authors.affiliation: Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, Pennsylvania 19081, USA.
authors.forename: Phuong A
authors.initials: PA
authors.lastname: Nguyen
authors.forename: Cinque S
authors.initials: CS
authors.lastname: Soto
authors.forename: Alexei
authors.initials: A
authors.lastname: Polishchuk
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Caputo
authors.forename: Chad D
authors.initials: CD
authors.lastname: Tatko
authors.forename: Chunlong
authors.initials: C
authors.lastname: Ma
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ohigashi
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Pinto
authors.forename: William F
authors.initials: WF
authors.lastname: DeGrado
authors.forename: Kathleen P
authors.initials: KP
authors.lastname: Howard