Abstract
Pulmonary surfactant protein C (SP-C) is one of the pulmonary surfactant proteins. It is a small, extremely hydrophobic peptide and has a highly conservative primary structure. The protein is normally palmitoylated on two adjacent cysteine residues. One arginine and one lysine residue are positively charged. SP-C enhances the adsorption of phospholipids into the air-water interface of the alveolar space. Structure and function of SP-C were investigated. Palmitoylated and non-palmitoylated human recombinant SP-C had a high α-helix content, but the orientation of the α-helix was dependent on the presence of palmitoyl chains. The physical properties of the acylated SP-C were different from the non-palmitoylated SP-C. Two forms of canine SP-C were isolated: monomeric palmitoylated SP-C, and dimeric, non-palmitoylated SP-C. The dimerization of SP-C had no impact on the physical properties of the protein. Binding of phospholipid-vesicles to the monolayer, and insertion of phospholipids into the monolayer was dependent on the positively charged amino acids.
In conclusion: 1 The positive charges of SP-C cause the binding of phospholipid-vesicles to the monolayer. 2 The calcium-independent insertion of phospholipids into the monolayer by SP-C is dependent on the orientation of the α-helix of SP-C. 3 This orientation is influenced by the presence of palmitoyl chains linked to the cysteine residues of the SP-C.
The investigations were supported by the Netherlands Foundation for Chemical Research (S.O.N.) with financial aid from the Netherlands Organization for Scientific Research (N.W.O.).
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Creuwels, L., Demel, R., Van Golde, L. et al. 54 CHARACTERIZATION OF SURFACTANT PROTEIN C (SP-C). Pediatr Res 36, 11 (1994). https://doi.org/10.1203/00006450-199407000-00054
Issue Date:
DOI: https://doi.org/10.1203/00006450-199407000-00054