title: Protein fold determined by paramagnetic magic-angle spinning solid-state NMR spectroscopy.
abstract: Biomacromolecules that are challenging for the usual structural techniques can be studied with atomic resolution by solid-state NMR spectroscopy. However, the paucity of distance restraints >5 Å, traditionally derived from measurements of magnetic dipole-dipole couplings between protein nuclei, is a major bottleneck that hampers such structure elucidation efforts. Here, we describe a general approach that enables the rapid determination of global protein fold in the solid phase via measurements of nuclear paramagnetic relaxation enhancements (PREs) in several analogues of the protein of interest containing covalently attached paramagnetic tags, without the use of conventional internuclear distance restraints. The method is demonstrated using six cysteine-EDTA-Cu(2+) mutants of the 56-residue B1 immunoglobulin-binding domain of protein G, for which ~230 longitudinal backbone (15)N PREs corresponding to distances of ~10-20 Å were obtained. The mean protein fold determined in this manner agrees with the X-ray structure with a backbone atom root-mean-square deviation of 1.8 Å.
authors.affiliation: Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA.
authors.forename: Ishita
authors.initials: I
authors.lastname: Sengupta
authors.forename: Philippe S
authors.initials: PS
authors.lastname: Nadaud
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Helmus
authors.forename: Charles D
authors.initials: CD
authors.lastname: Schwieters
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Jaroniec
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011487:Protein Conformation; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; C034284:IgG Fc-binding protein, Streptococcus; D011506:Proteins