1JQC

Mn substituted Ribonucleotide reductase R2 from E. Coli oxidized by hydrogen peroxide and hydroxylamine

Summary for 1JQC

• Entry DOI: 10.2210/pdb1jqc/pdb
• Related: 1JPR
• Descriptor: Protein R2 of ribonucleotide reductase, MANGANESE (II) ION, MERCURY (II) ION, ... (4 entities in total)
• Functional Keywords: ribonucleotide reductase r2, radical protein, mn substituted, oxidized by h2o2/nh2oh, oxidoreductase
• Biological source: Escherichia coli
• Total number of polymer chains: 2
• Total formula weight: 89681.15

Authors

Hogbom, M.,Andersson, M.E.,Nordlund, P. (deposition date: 2001-08-06, release date: 2001-08-22, Last modification date: 2024-03-13)

Primary citation

Hogbom, M.,Andersson, M.E.,Nordlund, P.
Crystal structures of oxidized dinuclear manganese centres in Mn-substituted class I ribonucleotide reductase from Escherichia coli: carboxylate shifts with implications for O2 activation and radical generation.
J.Biol.Inorg.Chem., 6:315-323, 2001

PubMed Abstract: The di-iron carboxylate proteins constitute a diverse class of non-heme iron enzymes performing a multitude of redox reactions. These reactions usually involve high-valent Fe-oxo species and are thought to be controlled by carboxylate shifts. Owing to their short lifetime, the intermediate structures have so far escaped structural characterization by X-ray crystallography. In an attempt to map the carboxylate conformations available to the protein during different redox states and different ligand environments, we have studied metal-substituted forms of the R2 protein of ribonucleotide reductase from Escherichia coli. In the present work we have solved the crystal structures of Mn-substituted R2 oxidized in two different ways. Oxidation was performed using either nitric oxide or a combination of hydrogen peroxide and hydroxylamine. The two structures are virtually identical, indicating that the oxidation states are the same, most likely a mixed-valent MnII-MnIII centre. One of the carboxylate ligands (D84) adopts a new, so far unseen, conformation, which could participate in the mechanism for radical generation in R2. E238 adopts a bridging-chelating conformation proposed to be important for proper O2 activation but not previously observed in the wild-type enzyme. Probable catalase activity was also observed during the oxidation with H2O2, indicating mechanistic similarities to the di-Mn catalases.

PubMed: 11315567
DOI: 10.1007/s007750000205

Experimental method

X-RAY DIFFRACTION (1.61 Å)