title: Isolation, Characterization, and Synthesis of the Barrettides: Disulfide-Containing Peptides from the Marine Sponge Geodia barretti.
abstract: Two disulfide-containing peptides, barrettides A (1) and B (2), from the cold-water marine sponge Geodia barretti are described. Those 31 amino acid residue long peptides were sequenced using mass spectrometry methods and structurally characterized using NMR spectroscopy. The structure of 1 was confirmed by total synthesis using the solid-phase peptide synthesis approach that was developed. The two peptides were found to differ only at a single position in their sequence. The three-dimensional structure of 1 revealed that these peptides possess a unique fold consisting of a long β-hairpin structure that is cross-braced by two disulfide bonds in a ladder-like arrangement. The peptides are amphipathic in nature with the hydrophobic and charged residues clustered on separate faces of the molecule. The barrettides were found not to inhibit the growth of either Escherichia coli or Staphylococcus aureus but displayed antifouling activity against barnacle larvae (Balanus improvisus) without lethal effects in the concentrations tested.
authors.forename: Bodil B
authors.initials: BB
authors.lastname: Carstens
authors.forename: K Johan
authors.initials: KJ
authors.lastname: Rosengren
authors.affiliation: Division of Pharmacognosy, Department of Medicinal Chemistry, Biomedical Center, Uppsala University , Box 574, SE-751 23 Uppsala, Sweden.
authors.forename: Sunithi
authors.initials: S
authors.lastname: Gunasekera
authors.affiliation: Division of Pharmacognosy, Department of Medicinal Chemistry, Biomedical Center, Uppsala University , Box 574, SE-751 23 Uppsala, Sweden.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Schempp
authors.affiliation: Division of Pharmacognosy, Department of Medicinal Chemistry, Biomedical Center, Uppsala University , Box 574, SE-751 23 Uppsala, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Bohlin
authors.affiliation: Department of Chemistry, Materials and Surfaces, SP Technical Research Institute of Sweden , Arvid Wallgrens Backe 20, SE-413 46 Göteborg, Sweden.
authors.forename: Mia
authors.initials: M
authors.lastname: Dahlström
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Clark
authors.affiliation: Division of Pharmacognosy, Department of Medicinal Chemistry, Biomedical Center, Uppsala University , Box 574, SE-751 23 Uppsala, Sweden.
authors.forename: Ulf
authors.initials: U
authors.lastname: Göransson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D057219:Biofouling / Q000517:prevention & control; D003080:Cold Temperature; D004220:Disulfides / Q000737:chemistry*; D047231:Geodia / Q000737:chemistry*; D007814:Larva / Q000187:drug effects; D008386:Marine Biology; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification*; D011487:Protein Conformation; D060327:Solid-Phase Synthesis Techniques; D013211:Staphylococcus aureus / Q000187:drug effects; D001468:Thoracica / Q000187:drug effects
chemical_list: D004220:Disulfides; D010456:Peptides, Cyclic; C000602711:barrettide A; C000602712:barrettide B