title: Structural analysis of the carboxyl terminal peptide from human chorionic gonadotropin beta-subunit by two-dimensional nuclear magnetic resonance spectroscopy.
abstract: OBJECTIVE
  Vaccines that target human chorionic gonadotropin (hCG) might be made more effective through greater understanding of the solution three-dimensional structure and behavior of the hormone.
  
  
  METHODS
  A 37-amino acid carboxyl terminal peptide of the hCG beta subunit was synthesized, purified, and analyzed by two-dimensional nuclear magnetic resonance spectroscopy.
  
  
  RESULTS
  Double-quantum filtered correlated spectroscopy data on the peptide in water at 4 degrees C reveals 27 multiplets in the peptide fingerprint region, as expected. A nuclear Overhauser effect spectroscopy spectrum shows several intraresidual peaks in the amide region but lacks clearly assignable interresidual signals.
  
  
  CONCLUSIONS
  By itself in water the carboxyl terminal peptide of hCG lacks defined secondary structure elements and is thus likely a random coil. The presence of beta turns appears possible although neither their existence nor their localization can be confirmed.
authors.affiliation: Department of Microbiology and Immunology, Stanford University School of Medicine, CA, USA.
authors.forename: E P
authors.initials: EP
authors.lastname: Rock
authors.forename: J
authors.initials: J
authors.lastname: Czaplicki
authors.forename: A
authors.initials: A
authors.lastname: Milon
mesh_terms: D000595:Amino Acid Sequence; D006063:Chorionic Gonadotropin / Q000737:chemistry*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry*; D011487:Protein Conformation; D013329:Structure-Activity Relationship
chemical_list: D006063:Chorionic Gonadotropin; D010446:Peptide Fragments