title: 13C and 15N NMR and time-resolved fluorescence depolarization study of bovine carbonic anhydrase--4-methylbenzenesulfonamide complex.
abstract: The influence of the binding of the high-affinity inhibitor, 4-methylbenzenesulfonamide, to the active site of bovine carbonic anhydrase B was studied by 15N- and 13C-NMR spectroscopy. The rotational correlation time dependence on temperature and concentration of the complex was determined by time-resolved fluorescence depolarization measurements. Our experiment provides evidence that the stoichiometry of the interaction of 4-methylbenzenesulfonamide with carbonic anhydrase B is 1:1 and the inhibitor is bound in anionic form. The 15N-NMR relaxation parameters confirm our previous conclusions about the presence of librational motions in the active site of carbonic anhydrase and indicate that the internal motion in the enzyme-inhibitor complex is more restricted than the backbone motion in the uncomplexed native enzyme.
authors.affiliation: Institute of Chemical Physics and Biophysics, Estonian Academy of Sciences, Tallinn, USSR.
authors.forename: J
authors.initials: J
authors.lastname: Jarvet
authors.forename: A
authors.initials: A
authors.lastname: Olivson
authors.forename: U
authors.initials: U
authors.lastname: Mets
authors.forename: M
authors.initials: M
authors.lastname: Pooga
authors.forename: R
authors.initials: R
authors.lastname: Aguraiuja
authors.forename: E
authors.initials: E
authors.lastname: Lippmaa
mesh_terms: D000818:Animals; D002247:Carbon Isotopes; D002256:Carbonic Anhydrases / Q000378:metabolism; D002417:Cattle; D005454:Fluorescence Polarization; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D009587:Nitrogen Isotopes; D013449:Sulfonamides; D014050:Toluene / Q000031:analogs & derivatives*; D014105:Tosyl Compounds / Q000378:metabolism; D000096926:Benzenesulfonamides
chemical_list: D002247:Carbon Isotopes; D002256:Carbonic Anhydrases; D009587:Nitrogen Isotopes; D013449:Sulfonamides; D014050:Toluene; D014105:Tosyl Compounds; C025417:4-toluenesulfonamide; D000096926:Benzenesulfonamides