The Three-His Triad in Dke1: Comparisons to the Classical Facial Triad
| Autor: | Michael L. Neidig, Grit Daniela Straganz, Graham R. Moran, Edward I. Solomon, Adrienne R. Diebold |
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| Rok vydání: | 2010 |
| Předmět: | |
| Zdroj: | Biochemistry. 49:6945-6952 |
| ISSN: | 1520-4995 0006-2960 |
| Popis: | The oxygen activating mononuclear non-heme ferrous enzymes catalyze a diverse range of chemistry yet typically maintain a common structural motif: two histidines and a carboxylate coordinating the iron center in a facial triad. A new FeII coordinating triad has been observed in two enzymes, diketone-cleaving dioxygenase, Dke1, and cysteine dioxygenase (CDO), and is composed of three histidine residues. The effect of this three-His motif in Dke1 on the geometric and electronic structure of the FeII center is explored via a combination of absorption, CD, MCD, and VTVH MCD spectroscopies and DFT calculations. This geometric and electronic structure of the three-His triad is compared to that of the classical (2-His-1-carboxylate) facial triad in the α-ketoglutarate (αKG)-dependent dioxygenases clavaminate synthase 2 (CS2) and hydroxyphenylpyruvate dioxygenase (HPPD). Comparison of the ligand fields at the FeII shows little difference between the three-His and 2-His-1-carboxylate facial triad sites. Acetylacet... |
| Databáze: | OpenAIRE |
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