title: Analysis of peptide rotational diffusion by homonuclear NMR.
abstract: The analysis of the rotational diffusion of a molecule using homonuclear NMR is investigated. The homonuclear longitudinal and transverse cross-relaxation rates, which can be quantitatively measured using off-Resonance Rotating frame nuclear Overhauser Effect Spectroscopy (ROESY), are used to build a distribution, which exhibits a solid-state-like pattern characteristic of the diffusion tensor. The distributions of the antimicrobial peptide ranalexin in water and in 30% of trifluoracetic acid (TFE) are compared, and the peptide rotational diffusion is shown to be more isotropic in water than in 30% TFE. This difference is further supported by the analysis of NMR ranalexin conformers in 30% TFE, and by the analysis of a molecular dynamics simulation of peptide in water.
authors.affiliation: Laboratoire de Biochimie Théorique, UPR 9080, IBPC, 11 rue Pierre et Marie Curie, F-75005 Paris, France. Therese.Malliavin@ibpc.fr
authors.forename: Thérèse E
authors.initials: TE
authors.lastname: Malliavin
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Giudice
mesh_terms: D016880:Anisotropy; D000900:Anti-Bacterial Agents / Q000737:chemistry*; D004058:Diffusion; D006845:Hydrocarbons, Fluorinated / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry*; D010456:Peptides, Cyclic / Q000737:chemistry*; D011485:Protein Binding; D014867:Water / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D006845:Hydrocarbons, Fluorinated; D010455:Peptides; D010456:Peptides, Cyclic; D014867:Water; C086618:ranalexin; C074585:trifluoroethene