A composition including a C terminal region having residues corresponding to 
a peptide identified by PDB ID: 1RG3; an N terminal region having residues corresponding to 
a peptide identified by PDB ID: 1RG4; and a 
disulfide linkage between the residues near the C terminal region and the N terminal region. A composition including an exogenous 
peptide comprising 
amino acid residues comprising a C terminal region; 
amino acid residues comprising an N terminal region; a 
helix-loop-
helix conformation between the residues comprising the C terminal region and the residues including the N terminal region; and at least one 
disulfide linkage between the residues comprising the C terminal region and the residues including N terminal region, wherein the residues including the C terminal region and the residues comprising the N terminal region have an amphiphatic property, and wherein the 
peptide has an a 
biological activity comparable to native surfactant 
protein SP-B. A method including delivering to a body a composition comprising an exogenous 
peptide having a 
biological activity comparable to native surfactant 
protein SP-B. A kit including an exogenous peptide having a 
biological activity comparable to native surfactant 
protein SP-B; and a treatment agent different from the peptide.