title: Sequential assignments and identification of secondary structure elements of the colicin E9 immunity protein in solution by homonuclear and heteronuclear NMR.
abstract: 1H-1H, 1H-15N, and 1H-1H-15N multidimensional NMR spectroscopic studies of the 86 amino acid protein that provides immunity against the DNase action of colicin E9 are reported. Through a combination of 2D NOESY and TOCSY and 3D TOCSY-HMQC, NOESY-HMQC, and HMQC-NOESY-HMQC experiments, almost complete 1H NMR and backbone 15N NMR assignments have been obtained, and the secondary structure of the protein has been partially elucidated. Approximately 50% of the protein forms three helices. The specificity determining region of the DNase immunity protein, identified from previously reported biochemical studies to include residues 32-40, is helical, indicating that the protein-protein interaction involves residues from at least one helix.
authors.affiliation: Schools of Chemical and Biological Sciences, University of East Anglia, Norwich, U.K.
authors.forename: M J
authors.initials: MJ
authors.lastname: Osborne
authors.forename: L Y
authors.initials: LY
authors.lastname: Lian
authors.forename: R
authors.initials: R
authors.lastname: Wallis
authors.forename: A
authors.initials: A
authors.lastname: Reilly
authors.forename: R
authors.initials: R
authors.lastname: James
authors.forename: C
authors.initials: C
authors.lastname: Kleanthous
authors.forename: G R
authors.initials: GR
authors.lastname: Moore
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D003087:Colicins / Q000037:antagonists & inhibitors*; D003851:Deoxyribonucleases / Q000378:metabolism; D004355:Drug Stability; D004926:Escherichia coli; D029968:Escherichia coli Proteins; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry; D012996:Solutions
chemical_list: D001426:Bacterial Proteins; D003087:Colicins; D029968:Escherichia coli Proteins; D011994:Recombinant Proteins; D012996:Solutions; C007104:colicin immunity proteins; C488859:immE9 protein, E coli; D003851:Deoxyribonucleases