title: Orientation and depth of surfactant protein B C-terminal helix in lung surfactant bilayers.
abstract: SP-B(CTERM) is a cationic amphipathic helical peptide and functional fragment composed of residues 63 to 78 of surfactant protein B (SP-B). Static oriented and magic angle spinning solid state NMR, along with molecular dynamics simulation was used to investigate its structure, orientation, and depth in lipid bilayers of several compositions, namely POPC, DPPC, DPPC/POPC/POPG, and bovine lung surfactant extract (BLES). In all lipid environments the peptide was oriented parallel to the membrane surface. While maintaining this approximately planar orientation, SP-B(CTERM) exhibited a flexible topology controlled by subtle variations in lipid composition. SP-B(CTERM)-induced lipid realignment and/or conformational changes at the level of the head group were observed using (31)P solid-state NMR spectroscopy. Measurements of the depth of SP-B(CTERM) indicated the peptide center positions ~8Å more deeply than the phosphate headgroups, a topology that may allow the peptide to promote functional lipid structures without causing micellization upon compression.
authors.affiliation: Université de Strasbourg/CNRS, UMR7177, Institut de Chimie, 4, rue Blaise Pascal, 67070 Strasbourg, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Bertani
authors.forename: Verica
authors.initials: V
authors.lastname: Vidovic
authors.forename: Tran-chin
authors.initials: TC
authors.lastname: Yang
authors.forename: Jennifer
authors.initials: J
authors.lastname: Rendell
authors.forename: Larry M
authors.initials: LM
authors.lastname: Gordon
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Waring
authors.forename: Burkhard
authors.initials: B
authors.lastname: Bechinger
authors.forename: Valerie
authors.initials: V
authors.lastname: Booth
mesh_terms: D000818:Animals; D002417:Cattle; D008051:Lipid Bilayers / Q000737:chemistry* / Q000378:metabolism; D008168:Lung / Q000737:chemistry* / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D017433:Protein Structure, Secondary; D037701:Pulmonary Surfactant-Associated Protein B / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D008051:Lipid Bilayers; D037701:Pulmonary Surfactant-Associated Protein B