title: RDC-enhanced structure calculation of a β-heptapeptide in methanol.
abstract: Residual dipolar couplings (RDCs) are a rich source of structural information that goes beyond the range covered by the nuclear Overhauser effect or scalar coupling constants. They can only be measured in partially oriented samples. RDC studies of peptides in organic solvents have so far been focused on samples in chloroform or DMSO. Here, we show that stretched poly(vinyl acetate) can be used for the partial alignment of a linear β-peptide with proteinogenic side chains in methanol.1DCH,1DNH, and2DHHRDCs were collected with this sample and included as restraints in a simulated annealing calculation. Incorporation of RDCs in the structure calculation process improves the long-range definition in the backbone of the resulting 314-helix and uncovers side-chain mobility. Experimental side-chain RDCs of the central leucine and valine residues are in good agreement with predicted values from a local three-state model. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Laboratorium für Organische Chemie, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland.
authors.forename: Carla
authors.initials: C
authors.lastname: Rigling
authors.affiliation: Laboratorium für Organische Chemie, ETH Zürich, Vladimir-Prelog-Weg 3, 8093, Zürich, Switzerland.
authors.forename: Marc-Olivier
authors.initials: MO
authors.lastname: Ebert
mesh_terms: D003198:Computer Simulation; D000432:Methanol / Q000737:chemistry*; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D009842:Oligopeptides / Q000737:chemistry*; D055585:Physical Phenomena; D011487:Protein Conformation; D012997:Solvents / Q000737:chemistry
chemical_list: D009842:Oligopeptides; D012997:Solvents; D000432:Methanol
keywords: 13C; 15N; 1H; NMR; beta-peptides; residual dipolar couplings; side-chain mobility; simulated annealing; stretched gels; structure determination