title: Structural and functional importance of the C-terminal part of the pulmonary surfactant polypeptide SP-C.
abstract: A synthetic non-palmitoylated form of the pulmonary surfactant protein SP-C and three peptides of different lengths corresponding to its N-terminal and middle parts were reconstituted into dipalmitoylglycerophosphocholine/phosphatidylglycerol (7:3, by mass) lipid bilayers. The adsorption properties of each reconstituted system were determined by measurement of the surface pressure after injection of the samples underneath an air/water interface. Attenuated total reflection infrared spectroscopy provided information about the structure and orientation of peptides in lipid bilayers. The hydrophobic C-terminal helix is crucial for the rapid adsorption as shortening of the C-terminal part drastically restricted this activity. The C-terminal amino acid sequence can however be replaced with that of the second transmembrane helix of bacteriorhodopsin without significantly modifying the adsorption properties. The data suggest that the hydrophobic C-terminal part allows the anchorage of SP-C in the lipid bilayer in such a manner that the N-terminal domain adopts an optimal conformation and orientation for the rapid adsorption of phospholipids at the air/water interface, and/or that a membrane-spanning helix as such is needed for this activity.
authors.affiliation: Service de Néonatologie, Hôpital des Enfants Reine Fabiola, Université Libre de Bruxelles, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Clercx
authors.forename: G
authors.initials: G
authors.lastname: Vandenbussche
authors.forename: T
authors.initials: T
authors.lastname: Curstedt
authors.forename: J
authors.initials: J
authors.lastname: Johansson
authors.forename: H
authors.initials: H
authors.lastname: Jörnvall
authors.forename: J M
authors.initials: JM
authors.lastname: Ruysschaert
mesh_terms: D000327:Adsorption; D000595:Amino Acid Sequence; D000818:Animals; D066298:In Vitro Techniques; D008051:Lipid Bilayers; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry*; D017433:Protein Structure, Secondary; D011510:Proteolipids / Q000737:chemistry*; D011663:Pulmonary Surfactants / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013329:Structure-Activity Relationship; D013552:Swine
chemical_list: D008051:Lipid Bilayers; D010455:Peptides; D010743:Phospholipids; D011510:Proteolipids; D011663:Pulmonary Surfactants