title: Nuclear magnetic resonance studies of the N-terminal fragment of adenosine diphosphate ribosylation factor 1 in micelles and bicelles: influence of N-myristoylation.
abstract: The N-terminal fragment of adenosine diphosphate (ADP) ribosylation factor 1 (ARF1) is proposed to be involved in the guanosine triphosphate- (GTP-) dependent, reversible association of the protein with membranes through the interaction of not only the N-linked myristoyl chain but also its highly conserved N-terminal hydrophobic residues. Based on the N-terminal sequence of this protein, specifically (13)C- and (15)N-labeled peptides were synthesized with and without an N-myristoyl anchor. The behavior, including structure, dynamics, and orientation, of these peptides in a lipid environment was then studied through a combination of solution (1)H nuclear magnetic resonance (NMR) techniques in micelles and heteronuclear solid-state NMR experiments in magnetically aligned bicelles. The work presented is an extension of the previously reported characterization of the myristoylated N-terminal fragment of ARF1 [Losonczi and Prestegard (1998) Biochemistry 37, 706-716] to include a comparison to a nonmyristoylated analogue. Results indicate that both myristoylated and nonmyristoylated peptides are alpha-helical in a lipid environment and that N-myristoylation does not greatly influence the structure of the peptides. Evidence is presented suggesting association of the peptides with bilayer disks through a combination of edge and surface interactions.
authors.affiliation: Complex Carbohydrate Research Center, University of Georgia, 220 Riverbend Road, Athens, Georgia 30602-4712, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Losonczi
authors.forename: F
authors.initials: F
authors.lastname: Tian
authors.forename: J H
authors.initials: JH
authors.lastname: Prestegard
mesh_terms: D020823:ADP-Ribosylation Factor 1 / Q000737:chemistry* / Q000378:metabolism; D000595:Amino Acid Sequence; D002247:Carbon Isotopes; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008244:Lysophosphatidylcholines / Q000737:chemistry; D008823:Micelles; D008969:Molecular Sequence Data; D019814:Myristic Acid / Q000737:chemistry / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism; D010742:Phospholipid Ethers / Q000737:chemistry
chemical_list: C052298:1,2-dihexadecyl-sn-glycero-3-phosphocholine; D002247:Carbon Isotopes; D008051:Lipid Bilayers; D008244:Lysophosphatidylcholines; D008823:Micelles; D010446:Peptide Fragments; D010742:Phospholipid Ethers; D019814:Myristic Acid; D020823:ADP-Ribosylation Factor 1; D004134:Dimyristoylphosphatidylcholine