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Titolo:
Determination of Fe-ligand bond lengths and the Fe-N-O bond angles in soybean ferrous and ferric nitrosylleghemoglobin alpha using multiple-scattering XAFS analyses
Autore:
Rich, AM; Ellis, PJ; Tennant, L; Wright, PE; Armstrong, RS; Lay, PA;
Indirizzi:
Univ Sydney, Sch Chem, Sydney, NSW 2006, Australia Univ Sydney Sydney NSWAustralia 2006 h Chem, Sydney, NSW 2006, Australia Scripps Clin, Dept Mol Biol, Res Inst, La Jolla, CA 92037 USA Scripps Clin La Jolla CA USA 92037 Biol, Res Inst, La Jolla, CA 92037 USA
Titolo Testata:
BIOCHEMISTRY
fascicolo: 50, volume: 38, anno: 1999,
pagine: 16491 - 16499
SICI:
0006-2960(199912)38:50<16491:DOFBLA>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
SOLUBLE GUANYLATE-CYCLASE; ELECTRON-PARAMAGNETIC-RESONANCE; NITRIC-OXIDE; CARBON-MONOXIDE; MOLECULAR STEREOCHEMISTRY; CRYSTAL-STRUCTURE; EXAFS ANALYSIS; HEME-PROTEINS; LEGHEMOGLOBIN; BINDING;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
63
Recensione:
Indirizzi per estratti:
Indirizzo: Lay, PA Univ Sydney, Sch Chem, Sydney, NSW 2006, Australia Univ Sydney Sydney NSW Australia 2006 Sydney, NSW 2006, Australia
Citazione:
A.M. Rich et al., "Determination of Fe-ligand bond lengths and the Fe-N-O bond angles in soybean ferrous and ferric nitrosylleghemoglobin alpha using multiple-scattering XAFS analyses", BIOCHEM, 38(50), 1999, pp. 16491-16499

Abstract

The NO adducts of leghemoglobin (Lb) are implicated in biological processes, but only the adduct with ferrous Lb (Lb(II)NO) has been characterized previously. We report the first characterization of ferric nitrosylleghemoglobin (Lb(III)NO) and XAS experiments performed on frozen aqueous solutions of Lb(II)NO and Lb(III)NO at 10 K. The XANES and electronic spectra of the NO adducts are similar in shape and energies to the myoglobin (Mb) analogues. The environment of the Fe atom has been refined using multiple-scattering(MS) analyses of the XAFS data. Fdr Lb(II)NO, the MS analysis resulted in an averaged Fe-N-p(pyrrole) distance of 2.02 Angstrom, an Fe-N-epsilon(imidazole) distance of 1.98 Angstrom, an Fe-N-No distance of 1.77 Angstrom, andan Fe-N-O angle of 147 degrees. The Fe-N-NO distance and Fe-N-O angle obtained from the analysis of Lb(II)NO are in good agreement with those determined crystallographically for [Fe(TPP)(NO)] (TPP, tetraphenylporphyrinato), with and without 1-methylimidazole (1-MeIm) as the sixth ligand, and the MSXAFS structures reported previously for the myoglobin (Mb(II)NO) analogue and [Fe(TPP)(NO)]. The MS analysis of Lb(III)NO yielded an average Fe-N-p distance of 2.00 Angstrom, an Fe-N-epsilon distance of 1.89 Angstrom, an Fe-N-NO distance of 1.68 Angstrom, and an Fe-N-O angle of 173 degrees. These bond lengths and angles are consistent with those determined previously for the myoglobin analogue (Mb(III)NO) and the crystal structures of the model complexes, [Fe-III(TPP)(NO)(OH2)](+) and [Fe(OEP)(NO)](+) (OEP, octaethylporphyrinato). The final XAFS R values were 16.1 and 18.2% for Lb(II)NO and Lb(III)NO, respectively.

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Documento generato il 26/11/20 alle ore 13:36:14