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Titolo:
ONE-DIMENSIONAL AND 2-DIMENSIONAL H-1-NMR STUDIES OF THE ACTIVE-SITE OF IRON(II) SUPEROXIDE-DISMUTASE FROM ESCHERICHIA-COLI
Autore:
MING LJ; LYNCH JB; HOLZ RC; QUE L;
Indirizzi:
UNIV S FLORIDA,DEPT CHEM TAMPA FL 33620 UNIV S FLORIDA,INST BIOMOLEC SCI TAMPA FL 33620 UNIV MINNESOTA,DEPT CHEM MINNEAPOLIS MN 55455
Titolo Testata:
Inorganic chemistry
fascicolo: 1, volume: 33, anno: 1994,
pagine: 83 - 87
SICI:
0020-1669(1994)33:1<83:OA2HSO>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
NUCLEAR MAGNETIC-RESONANCE; CYTOCHROME-C PEROXIDASE; PROTON NMR; CLOSTRIDIUM-PASTEURIANUM; HORSERADISH-PEROXIDASE; PSEUDOMONAS-OVALIS; LIGNIN PEROXIDASE; 2-DIMENSIONAL NMR; H-1-NMR SPECTRA; COMPLEXES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
41
Recensione:
Indirizzi per estratti:
Citazione:
L.J. Ming et al., "ONE-DIMENSIONAL AND 2-DIMENSIONAL H-1-NMR STUDIES OF THE ACTIVE-SITE OF IRON(II) SUPEROXIDE-DISMUTASE FROM ESCHERICHIA-COLI", Inorganic chemistry, 33(1), 1994, pp. 83-87

Abstract

The iron(II) superoxide dismutase (FeSOD) from Escherichia coli exhibits relatively sharp well-resolved paramagnetically shifted NMR signals. These signals can be associated with the endogenous ligands characterized by X-ray crystallography for the oxidized form (FeSOD)-S-III. Our results demonstrate that the active site remains intact upon reduction of the Fe(III) site, retaining the same coordination modes for thethree N-epsilon-coordinated His residues (presumably His-26, His-75, and His-162) and the Asp residue (presumably Asp-158). The N-H resonances of the coordinated histidines are found at 88, 43, and 37 ppm, while the signals at 24.5 (E), 19 (G), and 15 (J) ppm are assigned to theAsp residue by the observation of nuclear Overhauser effects (NOE) and bond correlations among the resonances. Distances of 1.9 and 2.4 Angstrom can be estimated between the protons E and G and the protons E and J, respectively, attributable to the -CbetaH2-CalphaH < spin systemof the Asp residue. The Asp assignments are corroborated by the observation of interresidue interactions between the CalphaH's of Asp-158 and Trp-160. The resonances of the latter residue are identified by NOEand scalar connectivities, the most critical assignment being the NalphaH at 22 ppm (F). According to the crystal structure of the corresponding enzyme from Psedumonas ovalis (Stoddard, B. L.; Howell, P. L.; Ringe, D.; Petsko, G. A, Biochemistry 1990, 29, 8885-8893), this protonis hydrogen-bonded to the free carboxylate oxygen of Asp-158. This interaction thus rationalizes the paramagnetic shift observed for signalF and its very slow exchange with solvent which occurs only upon long-term standing.

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Documento generato il 01/12/20 alle ore 12:30:49