title: Identification of slow motions in the reduced recombinant high-potential iron sulfur protein I (HiPIP I) from Ectothiorhodospira halophila via 15N rotating-frame NMR relaxation measurements.
abstract: Rotating-frame 15N relaxation rate (R1 rho) NMR experiments have been performed in order to study the dynamic behavior of the reduced recombinant high-potential iron-sulfur protein iso I (HiPIP I) from Ectothiorhodospira halophila, in the microsecond to ms time range. Measurements of R1 rho were performed as a function of the effective spinlock magnetic field amplitude by using both on and off-resonance radio frequency irradiation. The two data sets provided consistent results and were fit globally in order to identify possible exchange processes in an external loop of the reduced HiPIP I. The loop consists of residues 43-45 and the correlation time of the exchange process was determined to be 50 +/- 8 microseconds for the backbone nitrogen of Gln 44.
authors.affiliation: Department of Chemistry, University of Florence, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Banci
authors.forename: I C
authors.initials: IC
authors.lastname: Felli
authors.forename: D
authors.initials: D
authors.lastname: Koulougliotis
mesh_terms: D001419:Bacteria / Q000737:chemistry* / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D005973:Glutamine / Q000737:chemistry; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000235:genetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009587:Nitrogen Isotopes; D010084:Oxidation-Reduction; D045322:Photosynthetic Reaction Center Complex Proteins; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D009587:Nitrogen Isotopes; D045322:Photosynthetic Reaction Center Complex Proteins; D011994:Recombinant Proteins; C007943:high potential iron-sulfur protein; D005973:Glutamine