title: Proton-nuclear magnetic resonance studies of the aromatic spin systems of Escherichia coli adenylate kinase.
abstract: Escherichia coli adenylate kinase has a very well resolved proton nuclear magnetic resonance spectrum in the region containing signals from aromatic amino acid side-chains. We found that the protein is structurally stable over a wide pH range and renatures spontaneously after acidic as well as basic denaturation. Only one out of the three histidyl imidazole rings titrates on changing the pH and has a pka value of 7.6. Two-dimensional nuclear magnetic resonance spectroscopy studies allowed use to identify most of the enzyme's aromatic spin systems, and by investigation of a mutant protein we were able to assign the aromatic part of the spin system of Tyr24 unambiguously.
authors.affiliation: Max-Planck-Institute for Medical Research, Dept. of Biophysics, Heidelberg, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Bock
authors.forename: J
authors.initials: J
authors.lastname: Reinstein
authors.forename: M
authors.initials: M
authors.lastname: Brune
authors.forename: A
authors.initials: A
authors.lastname: Wittinghofer
authors.forename: P
authors.initials: P
authors.lastname: Rösch
mesh_terms: D000263:Adenylate Kinase; D004926:Escherichia coli / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D010770:Phosphotransferases; D011522:Protons
chemical_list: D011522:Protons; D010770:Phosphotransferases; D000263:Adenylate Kinase