title: Conformations of platypus venom C-type natriuretic peptide in aqueous solution and sodium dodecyl sulfate micelles.
abstract: Nuclear magnetic resonance spectroscopy was used to investigate the conformations of the platypus venom C-type natriuretic peptide A (OvCNPa) in aqueous solutions and in solutions containing sodium dodecyl sulfate (SDS) micelles. The chemically synthesized OvCNPa showed a substantial decrease in flexibility in aqueous solution at 10 degrees C, allowing the observation of medium- and long-range nuclear Overhauser enhancement (NOE) connectivities. Three-dimensional structures calculated using these data showed flexible and reasonably well-defined regions, the locations of which were similar in the two solvents. In aqueous solution, the linear part that spans residues 3-14 was basically an extended conformation while the cyclic portion, defined by residues 23-39, contained a series of beta-turns. The overall shape of the cyclic portion was similar to that observed for an atrial natriuretic peptide (ANP) variant in aqueous solution. OvCNPa adopted a different conformation in SDS micelles wherein the N-terminal region, defined by residues 2-10, was more compact, characterised by turns and a helix, while the cyclic region had turns and an overall shape that was fundamentally different from those structures observed in aqueous solution. The hydrophobic cluster, situated at the centre of the ring of the structure in aqueous solution, was absent in the structure in the presence of SDS micelles. Thus, OvCNPa interacts with SDS micelles and can possibly form ion-channels in cell membranes.
authors.affiliation: Department of Biochemistry, University of Sydney, Sydney, NSW 2006, Australia.
authors.forename: Allan M
authors.initials: AM
authors.lastname: Torres
authors.forename: Dianne
authors.initials: D
authors.lastname: Alewood
authors.forename: Paul F
authors.initials: PF
authors.lastname: Alewood
authors.forename: Clifford H
authors.initials: CH
authors.lastname: Gallagher
authors.forename: Philip W
authors.initials: PW
authors.lastname: Kuchel
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D008969:Molecular Sequence Data; D020098:Natriuretic Peptide, C-Type / Q000737:chemistry*; D010987:Platypus; D017433:Protein Structure, Secondary; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D014688:Venoms / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D008823:Micelles; D014688:Venoms; D014867:Water; D020098:Natriuretic Peptide, C-Type; D012967:Sodium Dodecyl Sulfate