title: beta-Endorphin: formation of alpha-helix in lipid solutions.
abstract: Human beta-endorphin adopts a partial helical conformation in aqueous solutions of cerebroside sulfate, ganglioside GM1, phosphatidylserine, and phosphatidic acid, but not of cerebroside and phosphatidylcholine, as evidenced by circular dichroic spectra. Addition of Ca2+ to the peptide in cerebroside sulfate solution can break up the helix; at 10 mM Ca2+ the peptide (12 microM) essentially exists in an unordered form. For comparison, sheep beta-lipotropin in acidic cerebroside sulfate solution (pH less than 4) also has a partial helical conformation of the complex between human beta-endorphin and lipids may be related to the opiatelike function of this peptide hormone.
mesh_terms: D000324:Adrenocorticotropic Hormone; D000595:Amino Acid Sequence; D002118:Calcium / Q000494:pharmacology; D002942:Circular Dichroism; D004723:Endorphins; D006017:Glycolipids / Q000494:pharmacology; D008055:Lipids / Q000494:pharmacology; D011487:Protein Conformation / Q000187:drug effects; D012997:Solvents; D013433:Sulfoglycosphingolipids; D008083:beta-Lipotropin
chemical_list: D004723:Endorphins; D006017:Glycolipids; D008055:Lipids; D012997:Solvents; D013433:Sulfoglycosphingolipids; D000324:Adrenocorticotropic Hormone; D008083:beta-Lipotropin; D002118:Calcium