title: C-terminal juxtamembrane region of full-length M2 protein forms a membrane surface associated amphipathic helix.
abstract: The influenza A M2 protein is a 97-residue integral membrane protein involved in viral budding and proton conductance. Although crystal and NMR structures exist of truncated constructs of the protein, there is disagreement between models and only limited structural data are available for the full-length protein. Here, the structure of the C-terminal juxtamembrane region (sites 50-60) is investigated in the full-length M2 protein using site-directed spin-labeling electron paramagnetic resonance (EPR) spectroscopy in lipid bilayers. Sites 50-60 were chosen for study because this region has been shown to be critical to the role the M2 protein plays in viral budding. Continuous wave EPR spectra and power saturation data in the presence of paramagnetic membrane soluble oxygen are consistent with a membrane surface associated amphipathic helix. Comparison between data from the C-terminal juxtamembrane region in full-length M2 protein with data from a truncated M2 construct demonstrates that the line shapes and oxygen accessibilities are remarkably similar between the full-length and truncated form of the protein.
authors.affiliation: Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, Pennsylvania, 19081.
authors.forename: Shenstone
authors.initials: S
authors.lastname: Huang
authors.forename: Bryan
authors.initials: B
authors.lastname: Green
authors.forename: Megan
authors.initials: M
authors.lastname: Thompson
authors.forename: Richard
authors.initials: R
authors.lastname: Chen
authors.forename: Jessica
authors.initials: J
authors.lastname: Thomaston
authors.forename: William F
authors.initials: WF
authors.lastname: DeGrado
authors.forename: Kathleen P
authors.initials: KP
authors.lastname: Howard
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008954:Models, Biological; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014763:Viral Matrix Proteins / Q000737:chemistry* / Q000378:metabolism*; D057074:Virus Release; D000086082:Viroporin Proteins
chemical_list: D008051:Lipid Bilayers; D011994:Recombinant Proteins; D014763:Viral Matrix Proteins; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins
keywords: amphipathic helix; electron paramagnetic resonance; full-length M2 protein; site-directed spin labeling; viral budding