title: NMR structure of oxidized glutaredoxin 3 from Escherichia coli.
abstract: A high precision NMR structure of oxidized glutaredoxin 3 [C65Y] from Escherichia coli has been determined. The conformation of the active site including the disulphide bridge is highly similar to those in glutaredoxins from pig liver and T4 phage. A comparison with the previously determined structure of glutaredoxin 3 [C14S, C65Y] in a complex with glutathione reveals conformational changes between the free and substrate-bound form which includes the sidechain of the conserved, active site tyrosine residue. In the oxidized form this tyrosine is solvent exposed, while it adopts a less exposed conformation, stabilized by hydrogen bonds, in the mixed disulfide with glutathione. The structures further suggest that the formation of a covalent linkage between glutathione and glutaredoxin 3 is necessary in order to induce these structural changes upon binding of the glutathione peptide. This could explain the observed low affinity of glutaredoxins for S-blocked glutathione analogues, in spite of the fact that glutaredoxins are highly specific reductants of glutathione mixed disulfides.
authors.affiliation: Center for Structural Biochemistry Karolinska Institutet, Huddinge, S-141 57, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Nordstrand
authors.forename: A
authors.initials: A
authors.lastname: Sandström
authors.forename: F
authors.initials: F
authors.lastname: Aslund
authors.forename: A
authors.initials: A
authors.lastname: Holmgren
authors.forename: G
authors.initials: G
authors.lastname: Otting
authors.forename: K D
authors.initials: KD
authors.lastname: Berndt
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D017124:Conserved Sequence; D003545:Cysteine / Q000378:metabolism; D004220:Disulfides / Q000737:chemistry / Q000378:metabolism; D004926:Escherichia coli / Q000737:chemistry*; D054477:Glutaredoxins; D005978:Glutathione / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010084:Oxidation-Reduction; D010088:Oxidoreductases; D010100:Oxygen / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation / Q000187:drug effects; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*; D019163:Reducing Agents / Q000378:metabolism / Q000494:pharmacology; D016415:Sequence Alignment; D012997:Solvents; D013379:Substrate Specificity; D013816:Thermodynamics; D014443:Tyrosine / Q000378:metabolism
chemical_list: D004220:Disulfides; D054477:Glutaredoxins; D011506:Proteins; D019163:Reducing Agents; D012997:Solvents; D014443:Tyrosine; D010088:Oxidoreductases; D005978:Glutathione; D003545:Cysteine; D010100:Oxygen