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| {{STRUCTURE_1jqc| PDB=1jqc | SCENE= }} | | {{STRUCTURE_1jqc| PDB=1jqc | SCENE= }} |
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| '''Mn substituted Ribonucleotide reductase R2 from E. Coli oxidized by hydrogen peroxide and hydroxylamine'''
| | ===Mn substituted Ribonucleotide reductase R2 from E. Coli oxidized by hydrogen peroxide and hydroxylamine=== |
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| ==Overview==
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| 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. | | The line below this paragraph, {{ABSTRACT_PUBMED_11315567}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 11315567 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_11315567}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Radical protein]] | | [[Category: Radical protein]] |
| [[Category: Ribonucleotide reductase r2]] | | [[Category: Ribonucleotide reductase r2]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 21:38:02 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 20:38:14 2008'' |
