title: 2D solid state NMR spectral simulation of 3(10), alpha, and pi-helices.
abstract: Transmembrane helices are more uniform in structure than similar helices in water soluble proteins. Solid state NMR of aligned bilayer samples is being increasingly used to characterize helical membrane protein structures. Traditional spectroscopic methods have difficulty distinguishing between helices with i to i + 3 (3(10)), i to i + 4 (alpha), and i to i + 5 (pi) hydrogen bonding topology. Here, we show that resonance patterns in PISEMA spectra simulated for these different helices show unique and striking features. The size and shape of these Polar Index Slant Angle (PISA) wheels, as well as the resonances per turn and clockwise versus counter-clockwise sequential connectivity of the resonances demonstrate how these different helical structures, if present as a uniform structure, will be readily distinguished, and characterized.
authors.affiliation: National High Magnetic Field Laboratory, Institute of Molecular Biophysics, Tallahassee, FL 32310, USA.
authors.forename: Sanguk
authors.initials: S
authors.lastname: Kim
authors.forename: T A
authors.initials: TA
authors.lastname: Cross
mesh_terms: D003198:Computer Simulation; D003461:Crystallography / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008565:Membrane Proteins / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary
chemical_list: D008565:Membrane Proteins; D010455:Peptides