title: NMR study of the phosphate-binding loops of Thermus thermophilus elongation factor Tu.
abstract: The phosphoryl-binding loops in the guanosine diphosphate binding domain of elongation factor Tu were studied by 15N heteronuclear proton-observe NMR methods. Five proton resonances were found below 10.5 ppm. One of these was assigned to the amide group of Lys 24, which is a conserved residue in the phosphoryl-binding concensus loop of purine nucleotide binding proteins. The uncharacteristic downfield proton shift is attributed to a strong hydrogen bond with a phosphate oxygen. The amide protons from the homologous lysines in N-ras p21 [Redfield, A.G., & Papastavros, M.Z. (1990) Biochemistry 29, 3509-3514] and the catalytic domain of Escherichia coli elongation factor Tu [Lowry, D.F., Cool, R.H., Redfield, A.G., & Parmeggiani, A. (1991) Biochemistry 30, 10872-10877] also resonate downfield in similar positions. We propose that the downfield shift of this lysine amide proton is a spectral marker for this class of proteins. We also have studied the temperature dependence of the downfield resonances and find a possible conformation change at 40 degrees C.
authors.affiliation: Department of Physics, Brandeis University, Waltham, Massachussetts 02254.
authors.forename: D F
authors.initials: DF
authors.lastname: Lowry
authors.forename: M R
authors.initials: MR
authors.lastname: Ahmadian
authors.forename: A G
authors.initials: AG
authors.lastname: Redfield
authors.forename: M
authors.initials: M
authors.lastname: Sprinzl
mesh_terms: D001665:Binding Sites; D005998:Glycine / Q000737:chemistry / Q000378:metabolism; D006153:Guanosine Diphosphate / Q000378:metabolism; D006860:Hydrogen Bonding; D008239:Lysine / Q000737:chemistry / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008345:Manganese / Q000378:metabolism / Q000494:pharmacology; D010444:Peptide Elongation Factor Tu / Q000737:chemistry* / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism*; D011487:Protein Conformation; D013113:Spin Labels; D013696:Temperature; D016963:Thermus thermophilus / Q000737:chemistry*
chemical_list: D010710:Phosphates; D013113:Spin Labels; D006153:Guanosine Diphosphate; D008345:Manganese; D010444:Peptide Elongation Factor Tu; D008274:Magnesium; D008239:Lysine; D005998:Glycine