High catalytic activity achieved with a mixed manganese-iron site in protein R2 of Chlamydia ribonucleotide reductase
| Autor: | Anders Ehrenberg, Nina Voevodskaya, Friedhelm Lendzian, Astrid Gräslund |
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| Rok vydání: | 2007 |
| Předmět: |
Stereochemistry
Iron Biophysics Specific activity chemistry.chemical_element Chlamydia trachomatis Manganese Biochemistry Catalysis chemistry.chemical_compound Structural Biology Ribonucleotide Reductases Genetics Manganese–iron cluster Ribonucleotide reductase Molecular Biology Diiron cluster chemistry.chemical_classification biology Electron Spin Resonance Spectroscopy Substrate (chemistry) Cell Biology Enzyme assay Enzyme chemistry biology.protein Deoxycytidine diphosphate EPR spectroscopy |
| Zdroj: | FEBS letters. 581(18) |
| ISSN: | 0014-5793 |
| Popis: | Ribonucleotide reductase (class I) contains two components: protein R1 binds the substrate, and protein R2 normally has a diferric site and a tyrosyl free radical needed for catalysis. In Chlamydia trachomatis RNR, protein R2 functions without radical. Enzyme activity studies show that in addition to a diiron cluster, a mixed manganese–iron cluster provides the oxidation equivalent needed to initiate catalysis. An EPR signal was observed from an antiferromagnetically coupled high-spin Mn(III)–Fe(III) cluster in a catalytic reaction mixture with added inhibitor hydroxyurea. The manganese–iron cluster in protein R2 confers much higher specific activity than the diiron cluster does to the enzyme. |
| Databáze: | OpenAIRE |
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