title: Interfacial behavior of recombinant forms of human pulmonary surfactant protein SP-C.
abstract: The behavior at air-liquid interfaces of two recombinant versions of human surfactant protein SP-C has been characterized in comparison with that of native palmitoylated SP-C purified from porcine lungs. Both native and recombinant proteins promoted interfacial adsorption of dipalmitoylphosphatidylcholine bilayers to a limited extent, but catalyzed very rapid formation of films from different lipid mixtures containing both zwitterionic and anionic phospholipids. Once at the interface, the recombinant variants exhibited compression-driven structural transitions, consistent with changes in the orientation of the deacylated N-terminal segment, which were not observed in the native protein. Compression isotherms of lipid/protein films suggest that the recombinant SP-C forms promote expulsion at high pressures of a higher number of lipid molecules per mole of protein than does native SP-C. A more dynamic conformation of the N-terminal segment in recombinant SP-C forms is likely also responsible for facilitating compression-driven condensation of domains in anionic phospholipid films as observed by epifluorescence microscopy. Finally, both native palmitoylated SP-C and the phenylalanine-containing recombinant versions facilitate similarly the repetitive compression-expansion dynamics of lipid/protein films, which were able to reach maximal surface pressures with practically no hysteresis along multiple quasi-static or dynamic cycles.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Valencia, Valencia, Spain.
authors.forename: Dunja
authors.initials: D
authors.lastname: Lukovic
authors.forename: Antonio
authors.initials: A
authors.lastname: Cruz
authors.forename: Azucena
authors.initials: A
authors.lastname: Gonzalez-Horta
authors.forename: Andrea
authors.initials: A
authors.lastname: Almlen
authors.forename: Tore
authors.initials: T
authors.lastname: Curstedt
authors.forename: Ismael
authors.initials: I
authors.lastname: Mingarro
authors.forename: Jesus
authors.initials: J
authors.lastname: Pérez-Gil
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010743:Phospholipids / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D037721:Pulmonary Surfactant-Associated Protein C / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism*; D013499:Surface Properties
chemical_list: D010446:Peptide Fragments; D010743:Phospholipids; D037721:Pulmonary Surfactant-Associated Protein C; D011994:Recombinant Proteins