title: Sequence-specific 1H NMR assignments and secondary structure of a lipid-associating peptide from human ApoC-I: an NMR study of an amphipathic helix motif.
abstract: The conformation of a synthetic peptide corresponding to residues 35-53 (SAKM-REWFSETFQKVKEKL) of human apolipoprotein C-I (57 amino acids) was studied by nuclear magnetic resonance and circular dichroism spectroscopy in water and in perdeuterated dodecylphosphocholine solution at 37 degrees C and pH 4.8. The proton resonances of the peptide in both solutions were assigned from TOCSY, NOESY and DQF-COSY experiments. In water solution, the peptide is predominantly "random", although nuclear Overhauser connectivity patterns and H alpha secondary shifts show a threshold population of nascent helical conformers. Upon the addition of 40-fold molar excess dodecylphosphocholine to the water solution, the peptide adopts a helical structure that extends throughout the sequence.
authors.affiliation: Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: G W
authors.initials: GW
authors.lastname: Buchko
authors.forename: A
authors.initials: A
authors.lastname: Rozek
authors.forename: Q
authors.initials: Q
authors.lastname: Zhong
authors.forename: R J
authors.initials: RJ
authors.lastname: Cushley
mesh_terms: D000595:Amino Acid Sequence; D053302:Apolipoprotein C-I; D001056:Apolipoproteins C / Q000737:chemistry*; D002942:Circular Dichroism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry*; D010767:Phosphorylcholine / Q000031:analogs & derivatives / Q000494:pharmacology; D017433:Protein Structure, Secondary
chemical_list: D053302:Apolipoprotein C-I; D001056:Apolipoproteins C; D010446:Peptide Fragments; D010767:Phosphorylcholine; C028810:dodecylphosphocholine