Unprecedented Mechanism Employed by theSalmonella entericaEutT ATP:CoIrrinoid Adenosyltransferase Precludes Adenosylation of Incomplete CoIIrrinoids
| Autor: | Jorge C. Escalante-Semerena, Paola E. Mera, Thomas C. Brunold, Theodore C. Moore, Kiyoung Park |
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| Rok vydání: | 2015 |
| Předmět: |
Stereochemistry
Catalysis Cofactor Article Enzyme catalysis chemistry.chemical_compound Corrinoid Bacterial Proteins Transferases medicine polycyclic compounds chemistry.chemical_classification biology Methylmalonyl-CoA mutase Electron Spin Resonance Spectroscopy Active site Salmonella enterica General Chemistry Cobalt General Medicine Adenosylcobalamin Vitamin B 12 Enzyme chemistry Biocatalysis biology.protein Cobamides medicine.drug |
| Zdroj: | Angewandte Chemie. 127:7264-7267 |
| ISSN: | 0044-8249 |
| DOI: | 10.1002/ange.201501930 |
| Popis: | Three distinct families of ATP:corrinoid adenosyltransferases (ACATs) exist that are capable of converting vitamin B12 derivatives to coenzyme B12 by catalyzing the thermodynamically challenging reduction of Co(II)rrinoids to form “super-nucleophilic” Co(I) intermediates. While the structures and mechanisms for the other two ACAT families have been studied extensively, little is known about the EutT enzymes beyond the fact that they exhibit a unique requirement for a divalent metal cofactor for enzymatic activity. In this study we have obtained compelling evidence that EutT converts cob(II)alamin to an effectively four-coordinate Co(II) species so as to facilitate Co(II) → Co(I) reduction. Intriguingly, EutT fails to promote axial ligand dissociation for the substrate analogue cob(II)inamide, a natural precursor of cob(II)alamin. This unique substrate specificity of EutT has important physiological implications. |
| Databáze: | OpenAIRE |
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