title: Determination of the positions of bound water molecules in the solution structure of reduced human thioredoxin by heteronuclear three-dimensional nuclear magnetic resonance spectroscopy.
abstract: The presence of bound water molecules in the solution structure of reduced human thioredoxin has been investigated using three-dimensional 1H rotating frame Overhauser 1H-15N multiple quantum coherence spectroscopy. It is demonstrated that the backbone amide protons of Lys21, Lys39, Lys82, Gly83 and Asn102, as well as the side-chain amide group of Asn102, are in close proximity to bound water molecules. Examination of the high-resolution solution structure of reduced human thioredoxin reveals that these results are best accounted for by four bound water molecules. Subsequent simulated annealing calculations carried out on the basis of interproton distance and hydrogen bonding restraints to the bound water molecules, supplemented by the original set of experimental restraints used in the calculation of the three-dimensional structure of human thioredoxin, permit a more precise localization of the bound water positions. Potential hydrogen bonds to these water molecules are described and a comparison is made to corresponding bound water molecules in the crystal structure of oxidized Escherichia coli thioredoxin.
authors.affiliation: Laboratory of Chemical Physics, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
authors.forename: J D
authors.initials: JD
authors.lastname: Forman-Kay
authors.forename: A M
authors.initials: AM
authors.lastname: Gronenborn
authors.forename: P T
authors.initials: PT
authors.lastname: Wingfield
authors.forename: G M
authors.initials: GM
authors.lastname: Clore
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D004926:Escherichia coli / Q000378:metabolism; D006801:Humans; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D010084:Oxidation-Reduction; D011487:Protein Conformation; D012996:Solutions; D013879:Thioredoxins / Q000737:chemistry* / Q000378:metabolism; D014867:Water
chemical_list: D012996:Solutions; D014867:Water; D013879:Thioredoxins