title: Engineering of the iron site in ribonucleotide reductase to a self-hydroxylating monooxygenase.
abstract: Protein R2 of ribonucleotide reductase contains a dinuclear ferric iron center adjacent to a tyrosyl radical in the interior of the protein matrix. A patch of hydrophobic residues surrounds the iron-radical cofactor. Its importance during the oxidative generation of the iron-radical cofactor was investigated by site-directed mutagenesis of Phe-208 to tyrosine. The mutant protein R2 F208Y has prominent absorption bands at 460 and 720 nm reminiscent of those in ferric-catecholate complexes. Resonance Raman spectroscopy shows that the iron center of R2 F208Y contains a bidentate catechol ligand. The mechanism for generation of this protein-derived dihydroxyphenylalanine may be similar to the catalytic cycle of methane monooxygenase.
authors.affiliation: Department of Molecular Biology, Stockholm University, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Ormö
authors.forename: F
authors.initials: F
authors.lastname: deMaré
authors.forename: K
authors.initials: K
authors.lastname: Regnström
authors.forename: A
authors.initials: A
authors.lastname: Aberg
authors.forename: M
authors.initials: M
authors.lastname: Sahlin
authors.forename: J
authors.initials: J
authors.lastname: Ling
authors.forename: T M
authors.initials: TM
authors.lastname: Loehr
authors.forename: J
authors.initials: J
authors.lastname: Sanders-Loehr
authors.forename: B M
authors.initials: BM
authors.lastname: Sjöberg
mesh_terms: D001483:Base Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D006900:Hydroxylation; D007501:Iron / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010084:Oxidation-Reduction; D010105:Oxygenases / Q000235:genetics*; D010649:Phenylalanine / Q000235:genetics; D015202:Protein Engineering; D012264:Ribonucleotide Reductases / Q000235:genetics* / Q000378:metabolism; D013059:Spectrum Analysis, Raman; D014443:Tyrosine / Q000235:genetics
chemical_list: D014443:Tyrosine; D010649:Phenylalanine; D007501:Iron; D010105:Oxygenases; D012264:Ribonucleotide Reductases