title: The activity of prolactin releasing peptide correlates with its helicity.
abstract: The prolactin releasing peptide (PrRP) is involved in regulating food intake and body weight homeostasis, but molecular details on the activation of the PrRP receptor remain unclear. C-terminal segments of PrRP with 20 (PrRP20) and 13 (PrRP8-20) amino acids, respectively, have been suggested to be fully active. The data presented herein indicate this is true for the wildtype receptor only; a 5-10-fold loss of activity was found for PrRP8-20 compared to PrRP20 at two extracellular loop mutants of the receptor. To gain insight into the secondary structure of PrRP, we used CD spectroscopy performed in TFE and SDS. Additionally, previously reported NMR data, combined with ROSETTANMR, were employed to determine the structure of amidated PrRP20. The structural ensemble agrees with the spectroscopic data for the full-length peptide, which exists in an equilibrium between α- and 3(10)-helix. We demonstrate that PrRP8-20's reduced propensity to form an α-helix correlates with its reduced biological activity on mutant receptors. Further, distinct amino acid replacements in PrRP significantly decrease affinity and activity but have no influence on the secondary structure of the peptide. We conclude that formation of a primarily α-helical C-terminal region of PrRP is critical for receptor activation.
authors: Vanderbilt University Center for Structural Biology, 5144B Biosci/MRBIII, 465 21st Avenue South, Nashville, TN 37232-8725.
authors: Stephanie H
authors: SH
authors: Deluca
authors: Daniel
authors: D
authors: Rathmann
authors: Annette G
authors: AG
authors: Beck-Sickinger
authors: Jens
authors: J
authors: Meiler
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D002942:Circular Dichroism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D056690:Prolactin-Releasing Hormone / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D055550:Protein Stability; D017433:Protein Structure, Secondary; D018013:Receptors, Neuropeptide / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013696:Temperature; D014269:Trifluoroacetic Acid / Q000737:chemistry
chemical_list: D056690:Prolactin-Releasing Hormone; D018013:Receptors, Neuropeptide; C400801:receptor, prolactin-releasing peptide; D012967:Sodium Dodecyl Sulfate; D014269:Trifluoroacetic Acid