SFTPC is a 197-residue protein made up of two halves: a unique N-terminal propeptide domain and a C-terminal BRICHOS domain. The around 100-aa long propeptide domain actually contains not only the cleaved part, but also the mature peptide. It can be further broken down into a 23-aa helical transmembrane propeptide proper, the mature secreted SP-C (24-58), and a linker (59-89) that connects to the BRICHOS domain.[8]
The propeptide of pulmonary surfactant C has an N-terminal alpha-helical segment whose suggested function was stabilization of the protein structure, since the mature peptide can irreversibly transform from its native alpha-helical structure to beta-sheet aggregates and form amyloid fibrils. The correct intracellular trafficking of proSP-C has also been reported to depend on the propeptide.[9]
The structure of the BRICHOS domain has been solved. Mutations in this domain also lead to amyloid fibrils made up of the mature peptide, suggesting a chaperone activity.[8]
Pérez-Gil J (2002). "Lipid-protein interactions of hydrophobic proteins SP-B and SP-C in lung surfactant assembly and dynamics". Pediatric Pathology & Molecular Medicine. 20 (6): 445–69. doi:10.1080/15227950152625783. PMID11699574.
Solarin KO, Wang WJ, Beers MF (2002). "Synthesis and post-translational processing of surfactant protein C". Pediatric Pathology & Molecular Medicine. 20 (6): 471–500. doi:10.1080/15227950152625792. PMID11699575.
Johansson J, Curstedt T, Robertson B (2002). "Artificial surfactants based on analogues of SP-B and SP-C". Pediatric Pathology & Molecular Medicine. 20 (6): 501–18. doi:10.1080/15227950152625800. PMID11699576.
Wood S, Yaremko ML, Schertzer M, Kelemen PR, Minna J, Westbrook CA (December 1994). "Mapping of the pulmonary surfactant SP5 (SFTP2) locus to 8p21 and characterization of a microsatellite repeat marker that shows frequent loss of heterozygosity in human carcinomas". Genomics. 24 (3): 597–600. doi:10.1006/geno.1994.1673. PMID7713515.
Hatzis D, Deiter G, deMello DE, Floros J (1994). "Human surfactant protein-C: genetic homogeneity and expression in RDS; comparison with other species". Experimental Lung Research. 20 (1): 57–72. doi:10.3109/01902149409064373. PMID8181452.