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.