Synthetic models for the zinc sites in the methionine synthases
| Autor: | Louise M. Liable-Sands, Charles G. Riordan, Show-Jen Chiou, Julie Innocent, Kin-Chung Lam, Arnold L. Rheingold |
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| Rok vydání: | 2001 |
| Předmět: |
Methionine
biology Molecular Structure chemistry.chemical_element Zinc Metathesis Toluene Medicinal chemistry 5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase Inorganic Chemistry Bond length chemistry.chemical_compound chemistry Models Chemical biology.protein Molecule Organic chemistry Methionine synthase Protonolysis Physical and Theoretical Chemistry |
| Zdroj: | Inorganic chemistry. 39(19) |
| ISSN: | 0020-1669 |
| Popis: | The syntheses and molecular structures of a series of tetrahedral zinc complexes designed to model the active sites in Escherichia coli methionine synthases are reported. [PhTttBu]ZnBr (PhTttBu = phenyltris((tert-butylthio)-methyl)borate) was prepared and characterized crystallographically to provide entry into [S3]ZnX complexes. Metathesis with KSPh yielded the phenylthiolato complex, [PhTttBu]Zn(SPh), which represents a structural mimic of the homocysteine ligated form of the enzyme. Alternatively, [S2N]ZnX (X = Br, CH3, SPh) species were prepared using the new mixed-donor ligands, [Ph(pz)BttBu] (phenyl(pyrazolyl)bis((tert-butylthio)methyl)borate) and [Ph(pztBu)BttBu] (phenyl(3-tert-butylpyrazolyl)bis((tert- butylthio)methyl)borate). Protonolysis of [Ph(pztBu)-BttBu]Zn(CH3) by PhSH in toluene yielded [Ph(pztBu)BttBu]Zn(SPh), a synthetic analogue of the homocysteine ligated form of cobalamin-independent methionine synthase (Met E). The average Zn-S bond distance in [Ph-(pztBu)BttBu]Zn(SPh) of 2.37 A compares well with the EXAFS-derived distance of 2.31 A found in the homocysteine-bound form of Met E. |
| Databáze: | OpenAIRE |
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