title: Sequence of two gonadotropin releasing hormones from tunicate suggest an important role of conformation in receptor activation.
abstract: The primary structure of two forms of gonadotropin releasing hormone (GnRH) from tunicate (Chelyosoma productum) have been determined based on mass spectrometric and chemical sequence analyses. The peptides, tunicate GnRH-I and -II, contain features unprecedented in vertebrate GnRH. Tunicate GnRH-I contains a putative salt bridge between Asp5 and Lys8. A GnRH analog containing a lactam bridge between Asp5 and Lys8 was found to increase release of estradiol compared with that of the native tunicate GnRH-I and -II. Tunicate GnRH-II contains a cysteine residue and was isolated as a dimeric peptide. These motifs suggest that the conformation plays an important role in receptor activation.
authors.affiliation: The Clayton Foundation, Laboratories for Peptide Biology, The Salk Institute, La Jolla, CA 92037, USA. craig@salk.edu
authors.forename: A G
authors.initials: AG
authors.lastname: Craig
authors.forename: W H
authors.initials: WH
authors.lastname: Fischer
authors.forename: M
authors.initials: M
authors.lastname: Park
authors.forename: J E
authors.initials: JE
authors.lastname: Rivier
authors.forename: B D
authors.initials: BD
authors.lastname: Musselman
authors.forename: J F
authors.initials: JF
authors.lastname: Powell
authors.forename: S M
authors.initials: SM
authors.lastname: Reska-Skinner
authors.forename: M O
authors.initials: MO
authors.lastname: Prakash
authors.forename: G O
authors.initials: GO
authors.lastname: Mackie
authors.forename: N M
authors.initials: NM
authors.lastname: Sherwood
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019281:Dimerization; D004958:Estradiol / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives / Q000737:chemistry* / Q000494:pharmacology; D010446:Peptide Fragments / Q000737:chemistry; D011487:Protein Conformation; D011966:Receptors, LHRH / Q000378:metabolism*; D017421:Sequence Analysis; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014561:Urochordata / Q000737:chemistry* / Q000378:metabolism
chemical_list: D010446:Peptide Fragments; D011966:Receptors, LHRH; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol