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Structural and functional importance of the C-terminal part of the pulmonary surfactant polypeptide SP-C.

par Clercx, Anne ;Vandenbussche, G;Curstedt, T;Johansson, J;Jornvall, H.;Ruysschaert, Jean Marie
Référence European journal of biochemistry / FEBS, 229, 2, page (465-472)
Publication Publié, 1995-04

Article révisé par les pairs

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Résumé :

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.