title: Magic angle spinning NMR spectroscopy of thioredoxin reassemblies.
abstract: Differentially isotopically enriched 1-73((13)C,(15)N)/74-108((15)N) and 1-73((15)N)/74-108((13)C,(15)N) Escherichia coli thioredoxin reassemblies prepared by fragment complementation were investigated by high-resolution magic angle spinning solid-state NMR spectroscopy. Nearly complete resonance assignments, secondary and tertiary structure analysis are reported for 1-73((13)C,(15)N)/74-108((15)N) reassembled thioredoxin. Temperature dependence of the dipolar-assisted rotational resonance (DARR) spectra reveals the residues undergoing intermediate timescale motions at temperatures below - 15 degrees C. Analysis of the DARR intensity buildups as a function of mixing time in these reassemblies indicates that at long mixing times medium- and long-range cross-peaks do not experience dipolar truncation, suggesting that isotopic dilution is not required for gaining nontrivial distance restraints for structure calculations.
authors.affiliation: Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.forename: Sivakumar
authors.initials: S
authors.lastname: Paramasivam
authors.forename: Dabeiba
authors.initials: D
authors.lastname: Marulanda
authors.forename: Marcela
authors.initials: M
authors.lastname: Cataldi
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Tasayco
authors.forename: Tatyana
authors.initials: T
authors.lastname: Polenova
mesh_terms: D002247:Carbon Isotopes; D029968:Escherichia coli Proteins; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009038:Motion; D009587:Nitrogen Isotopes; D011487:Protein Conformation; D013696:Temperature; D013879:Thioredoxins / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D029968:Escherichia coli Proteins; D009587:Nitrogen Isotopes; D013879:Thioredoxins