title: Identification of solvent-exposed regions of an FK-506 analog, ascomycin, bound to FKBP using a paramagnetic probe.
abstract: The solvent-exposed regions of (U-13C)ascomycin when bound to its putative target protein, FKBP, have been identified based on the different proton longitudinal relaxation rates (R1 = 1/T1) measured in the absence and presence of the paramagnetic relaxation reagent, 4-hydroxy-2,2,6,6-tetramethyl-piperidinyl-1-oxy (HyTEMPO). The proton T1S of bound ascomycin were determined using a pulse sequence (T1-HMQC) which consists of a 180 degree proton pulse and a variable delay (tau) followed by a heteronuclear multiple quantum correlation (HMQC) experiment. The solvent-exposed regions of ascomycin determined by these experiments are compared to NOE data in which ascomycin/FKBP contacts were identified and to the X-ray structure of the FK-506/FKBP complex.
authors.affiliation: Pharmaceutical Discovery Division, Abbott Laboratories, Abbott Park, IL 60064.
authors.forename: A M
authors.initials: AM
authors.lastname: Petros
authors.forename: P
authors.initials: P
authors.lastname: Neri
authors.forename: S W
authors.initials: SW
authors.lastname: Fesik
mesh_terms: D001665:Binding Sites; D002247:Carbon Isotopes; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D003497:Cyclic N-Oxides; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D008968:Molecular Conformation; D011485:Protein Binding; D011487:Protein Conformation; D013113:Spin Labels; D016559:Tacrolimus / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism*; D022021:Tacrolimus Binding Proteins; D014961:X-Ray Diffraction
chemical_list: D002247:Carbon Isotopes; D002352:Carrier Proteins; D003497:Cyclic N-Oxides; D013113:Spin Labels; C058028:immunomycin; D022021:Tacrolimus Binding Proteins; C001803:tempol; D016559:Tacrolimus