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| | {{STRUCTURE_1h0n| PDB=1h0n | SCENE= }} | | {{STRUCTURE_1h0n| PDB=1h0n | SCENE= }} |
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| - | '''COBALT SUBSTITUTION OF MOUSE R2 RIBONUCLEOTIDE REDUCTASE TO MODEL THE REACTIVE DIFERROUS STATE'''
| + | ===COBALT SUBSTITUTION OF MOUSE R2 RIBONUCLEOTIDE REDUCTASE TO MODEL THE REACTIVE DIFERROUS STATE=== |
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| - | ==Overview==
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| - | The R2 dimer of mouse ribonucleotide reductase contains a dinuclear iron-oxygen cluster and tyrosyl radical/subunit. The dinuclear diferrous form reacts with dioxygen to generate the tyrosyl radical essential for the catalytic reaction that occurs at the R1 dimer. It is important to understand how the reactivity toward oxygen is related to the crystal structure of the dinuclear cluster. For the mouse R2 protein, no structure has been available with a fully occupied dinuclear metal ion site. A cobalt substitution of mouse R2 was performed to produce a good model for the very air-sensitive diferrous form of the enzyme. X-band EPR and light absorption studies (epsilon(550 nm) = 100 mm(-1) cm(-1)/Co(II)) revealed a strong cooperative binding of cobalt to the dinuclear site. In perpendicular mode EPR, the axial signal from mouse R2 incubated with Co(II) showed a typical S = 3/2 Co(II) signal, and its low intensity indicated that the majority of the Co(II) bound to R2 is magnetically coupled. In parallel mode EPR, a typical integer spin signal (M(s) = +/-3) with g approximately 12 is observed at 3.6 K and 10 K, showing that the two Co(II) ions (S = 3/2) in the dinuclear site are ferromagnetically coupled. We have solved the 2.4 A crystal structure of the Co(II)-substituted R2 with a fully occupied dinuclear cluster. The bridging Co(II) carboxylate ligand Glu-267 adopts an altered orientation compared with its counterpart Glu-238 in Escherichia coli R2. This might be important for proper O(2) activation of the more exposed native diferrous site in mouse R2 compared with E. coli R2. | + | The line below this paragraph, {{ABSTRACT_PUBMED_12087093}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 12087093 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_12087093}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Oxidoreductase]] | | [[Category: Oxidoreductase]] |
| | [[Category: Ribonucleotide reductase]] | | [[Category: Ribonucleotide reductase]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 18:15:51 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 06:25:28 2008'' |
Revision as of 03:25, 1 July 2008
Template:STRUCTURE 1h0n
COBALT SUBSTITUTION OF MOUSE R2 RIBONUCLEOTIDE REDUCTASE TO MODEL THE REACTIVE DIFERROUS STATE
Template:ABSTRACT PUBMED 12087093
About this Structure
1H0N is a Single protein structure of sequence from Mus musculus. Full crystallographic information is available from OCA.
Reference
Cobalt substitution of mouse R2 ribonucleotide reductase as a model for the reactive diferrous state Spectroscopic and structural evidence for a ferromagnetically coupled dinuclear cobalt cluster., Strand KR, Karlsen S, Andersson KK, J Biol Chem. 2002 Sep 13;277(37):34229-38. Epub 2002 Jun 26. PMID:12087093
Page seeded by OCA on Tue Jul 1 06:25:28 2008
