| First Author | Xing G | Year | 2006 |
| Journal | Biochemistry | Volume | 45 |
| Issue | 17 | Pages | 5393-401 |
| PubMed ID | 16634620 | Mgi Jnum | J:108410 |
| Mgi Id | MGI:3623876 | Doi | 10.1021/bi0519607 |
| Citation | Xing G, et al. (2006) A coupled dinuclear iron cluster that is perturbed by substrate binding in myo-inositol oxygenase. Biochemistry 45(17):5393-401 |
| abstractText | myo-Inositol oxygenase (MIOX) uses iron as its cofactor and dioxygen as its cosubstrate to effect the unique, ring-cleaving, four-electron oxidation of its cyclohexan-(1,2,3,4,5,6-hexa)-ol substrate to d-glucuronate. The nature of the iron cofactor and its interaction with the substrate, myo-inositol (MI), have been probed by electron paramagnetic resonance (EPR) and Mossbauer spectroscopies. The data demonstrate the formation of an antiferromagnetically coupled, high-spin diiron(III/III) cluster upon treatment of solutions of Fe(II) and MIOX with excess O(2) or H(2)O(2) and the formation of an antiferromagnetically coupled, valence-localized, high-spin diiron(II/III) cluster upon treatment with either limiting O(2) or excess O(2) in the presence of a mild reductant (e.g., ascorbate). Marked changes to the spectra of both redox forms upon addition of MI and analogy to changes induced by binding of phosphate to the diiron(II/III) cluster of the protein phosphatase, uteroferrin, suggest that MI coordinates directly to the diiron cluster, most likely in a bridging mode. The addition of MIOX to the growing family of non-heme diiron oxygenases expands the catalytic range of the family beyond the two-electron oxidation (hydroxylation and dehydrogenation) reactions catalyzed by its more extensively studied members such as methane monooxygenase and stearoyl acyl carrier protein Delta(9)-desaturase. |
