title: An unusual peptide from Conus villepinii: synthesis, solution structure, and cardioactivity.
abstract: The venom of marine cone snails contains a variety of conformationally constrained peptides utilized by the animal to capture prey. Besides numerous conotoxins, which are characterized by complex disulfide patterns, other peptides with only a single disulfide bridge were isolated from different conus species. Here, we report the synthesis, structure elucidation and biological evaluation of the novel C-terminally amidated decapeptide CCAP-vil, PFc[CNSFGC]YN-NH(2), from Conus villepinii. The linear precursor peptide was generated by standard solid phase synthesis. Oxidation of the cysteine residues to yield the disulfide-bridged peptide was investigated under different conditions, including several ionic liquids (ILs) as new biocompatible reaction media. Among the examined ILs, 1-ethyl-3-methylimidazolium tosylate ([C(2)mim][OTs]) was most efficient for CCAP-vil oxidative folding, since oxidation occurred without any byproduct formation. The structure of CCAP-vil was determined by NMR methods in aqueous solution and revealed a loop structure adopting a type(I) beta-turn between residues 4-7 imposed by the flanking disulfide bridge. The amino acid side chains of Pro(1), Phe(2), Phe(6) and Tyr(9) point in three directions away from the cyclic core into the solvent creating a rather hydrophobic surface of the molecule. Based on sequence homology to cardioactive peptides (CAPs) from gastropods and arthropods, such as PFc[CNAFTGC]-NH(2) (CCAP), the influence of CCAP-vil on heart rate using zebrafish embryos was investigated. CCAP-vil reduced the heart rate immediately upon injection into the heart as well as upon indirect application indicating an opposite effect to the cardioaccelerating CCAP.
authors.affiliation: Center for Molecular Biomedicine, Department of Biochemistry, Peptide Chemistry Group, Friedrich Schiller University, Hans-Knöll-Strasse 2, D-07745 Jena, Germany.
authors.forename: Alesia
authors.initials: A
authors.lastname: Miloslavina
authors.forename: Christina
authors.initials: C
authors.lastname: Ebert
authors.forename: Daniel
authors.initials: D
authors.lastname: Tietze
authors.forename: Oliver
authors.initials: O
authors.lastname: Ohlenschläger
authors.forename: Christoph
authors.initials: C
authors.lastname: Englert
authors.forename: Matthias
authors.initials: M
authors.lastname: Görlach
authors.forename: Diana
authors.initials: D
authors.lastname: Imhof
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020916:Conotoxins / Q000737:chemistry* / Q000494:pharmacology; D052078:Conus Snail / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000378:metabolism; D006339:Heart Rate / Q000187:drug effects; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D009842:Oligopeptides / Q000737:chemistry* / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000737:chemistry* / Q000494:pharmacology; D011487:Protein Conformation; D015027:Zebrafish
chemical_list: C552030:CCAP-vil peptide, Conus villepinii; D020916:Conotoxins; D009842:Oligopeptides; D010456:Peptides, Cyclic