title: Orientational and motional narrowing of solid-state NMR lineshapes of uniaxially aligned membrane proteins.
abstract: A unified theory for the NMR line shapes of aligned membrane proteins arising from uniaxial disorder (mosaic spread) and global rotational diffusion about the director axis is presented. A superoperator formalism allows one to take into account the effects of continuous radiofrequency irradiation and frequency offsets in the presence of dynamics. A general method based on the Stochastic Liouville Equation makes it possible to bridge the static and dynamic limits in a single model. Simulations of solid-state NMR spectra are performed for a uniform α helix by considering orientational disorder and diffusion of the helix as a whole relative to the alignment axis. The motional narrowing of the resonance lines is highly inhomogeneous and can be used as an additional angular restraint in structure calculations. Experimental solid-state NMR spectra of Pf1 coat protein support the conclusions of the theory for two limiting cases. The static disorder dominates the (15)N NMR spectra of Pf1 aligned on a phage, while fast uniaxial diffusion provides a line narrowing mechanism for the Pf1 protein reconstituted in magnetically aligned bicelles.
authors.affiliation: Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, North Carolina 27695-8240, USA.
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Nevzorov
mesh_terms: D025561:Bacteriophage Pf1 / Q000378:metabolism; D036022:Capsid Proteins / Q000737:chemistry; D004058:Diffusion; D008565:Membrane Proteins / Q000737:chemistry*; D009587:Nitrogen Isotopes / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular
chemical_list: D036022:Capsid Proteins; D008565:Membrane Proteins; D009587:Nitrogen Isotopes