title: Conformational backbone dynamics of the cyclic decapeptide antamanide. Application of a new multiconformational search algorithm based on NMR data.
abstract: A general procedure for the analysis of biomolecular structures by NMR in the presence of rapid conformational dynamics has been applied to the study of the cyclic decapeptide antamanide. Two-dimensional experiments, relaxation measurements in the rotating frame, and homo- and heteronuclear coupling constant determinations have been used to characterize the dynamic properties of the molecule, in combination with a novel search algorithm for investigating multiconformational equilibria. Direct evidence for the presence of a conformational exchange process with an activation energy of approximately 20 kJ mol-1 and an exchange lifetime of approximately 25 microseconds at 320 K has been obtained from rotating frame relaxation measurements. This evidence is combined with the information derived from the multiconformational search algorithm MEDUSA to propose sets of structures that coexist in a dynamic exchange equilibrium.
authors.affiliation: Laboratorium für Physikalische Chemie, Eidgenössische Technische Hochschule, Zürich, Switzerland.
authors.forename: M J
authors.initials: MJ
authors.lastname: Blackledge
authors.forename: R
authors.initials: R
authors.lastname: Brüschweiler
authors.forename: C
authors.initials: C
authors.lastname: Griesinger
authors.forename: J M
authors.initials: JM
authors.lastname: Schmidt
authors.forename: P
authors.initials: P
authors.lastname: Xu
authors.forename: R R
authors.initials: RR
authors.lastname: Ernst
mesh_terms: D000465:Algorithms; D000595:Amino Acid Sequence; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008433:Mathematics; D008969:Molecular Sequence Data; D010456:Peptides, Cyclic / Q000737:chemistry*; D011487:Protein Conformation; D013816:Thermodynamics
chemical_list: D010456:Peptides, Cyclic; C100265:antamanide