title: Conformation of the propeptide domain of factor IX.
abstract: The propeptide domain in the precursor forms of blood clotting proteins contains the recognition sequences for gamma-carboxylase. In hemophilia B, several point mutations in this propeptide domain are responsible for the inherited disease. A peptide containing the propeptide sequence of factor IX was synthesized by solid phase methods. Two dimensional 1H-NMR and CD studies indicate that this peptide motif adopts an alpha-helical structure in a 40% trifluoroethanol-containing aqueous solution. The results suggest that the amphipathic alpha-helix within the propeptide domain of factor IX could create a recognition surface for gamma-carboxylase. The influences of mutations and their relationship with the alpha-helical structure are discussed.
mesh_terms: D015055:1-Carboxyglutamic Acid / Q000378:metabolism; D000595:Amino Acid Sequence; D001665:Binding Sites; D002262:Carboxy-Lyases / Q000378:metabolism; D002942:Circular Dichroism; D005164:Factor IX / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry; D011487:Protein Conformation; D011498:Protein Precursors / Q000737:chemistry*; D017433:Protein Structure, Secondary; D011516:Prothrombin / Q000737:chemistry
chemical_list: D010446:Peptide Fragments; D011498:Protein Precursors; D015055:1-Carboxyglutamic Acid; D011516:Prothrombin; D005164:Factor IX; D002262:Carboxy-Lyases