Reactivity of Five-Coordinate Models for the Thiolate-Ligated Fe Site of Nitrile Hydratase
| Autor: | Andrew M. Nienstedt, Julie A. Kovacs, Steven C. Shoner, Jerry A. Cowen, David M. Barnhart, Jeffrey J. Ellison |
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| Rok vydání: | 1998 |
| Předmět: |
Coordination sphere
Chemistry Ligand Coordination number General Chemistry Photochemistry Biochemistry Catalysis law.invention Crystallography chemistry.chemical_compound Colloid and Surface Chemistry Nitrile hydratase law Hexafluorophosphate Reactivity (chemistry) Azide Electron paramagnetic resonance |
| Zdroj: | Journal of the American Chemical Society. 120:5691-5700 |
| ISSN: | 1520-5126 0002-7863 |
| Popis: | To examine inhibitor binding to an iron site resembling that of the metalloenzyme nitrile hydratase (NHase), a coordinatively unsaturated, five-coordinate FeIII thiolate complex was synthesized, and its reactivity examined. Ferricinium hexafluorophosphate induced oxidation of gem-dimethyl-protected [FeIIS2Me2N3(Pr,Pr)] affords the chiral, five-coordinate complex [FeIIIS2Me2N3(Pr,Pr)]+ (2) in reasonable yields. The magnetic properties and EPR of 2 are consistent with an S = 1/2 ground state. This unusual spin state, in conjunction with the low coordination number, of 2 result in unusually short Fe−S bonds (2.15(2) A). Ligand constraints distort the S−Fe−N angles in 2 and create an open (132.3(1)°) reactive site. Azide binds to this site to afford a model for the azide-inhibited form of NHase [FeIIIS2Me2N3(Pr,Pr)(N3)] (3). In MeOH azide binds reversibly, whereas in MeCN it binds irreversibly. This demonstrates that the secondary coordination sphere (i.e., the solvent, or possibly a protein binding pocket) c... |
| Databáze: | OpenAIRE |
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