title: Determination of the backbone conformation of secretin by restrained molecular dynamics on the basis of interproton distance data.
abstract: The backbone conformation of the 27-residue polypeptide hormone secretin has been investigated using nuclear magnetic resonance spectroscopy and restrained molecular dynamics calculations under conditions where it adopts a fully ordered structure (40% v/v trifluoroethanol). The basis for the restrained molecular dynamics calculations consists of 52 nuclear-Overhauser-enhancement-derived interproton distance restraints involving the NH, C alpha H and C beta H protons. It is shown that convergence to similar extended structures is achieved starting from four different initial structures, namely an alpha helix, a mixed alpha/beta structure, a beta strand and a polyproline helix. The converged structures are made up of short N- and C-terminal strand-like regions and a central region comprising two irregular helices connected by a 'half-turn'.
authors.affiliation: Max-Planck-Institut für Biochemie, Martinsried bei München, Federal Republic of Germany.
authors.forename: G M
authors.initials: GM
authors.lastname: Clore
authors.forename: M
authors.initials: M
authors.lastname: Nilges
authors.forename: A
authors.initials: A
authors.lastname: Brünger
authors.forename: A M
authors.initials: AM
authors.lastname: Gronenborn
mesh_terms: D004735:Energy Transfer; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D011487:Protein Conformation; D011522:Protons; D012633:Secretin / Q000032:analysis*; D012984:Software
chemical_list: D011522:Protons; D012633:Secretin