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Your search keyword '"Della Longa S"' showing total 5 results
Start Over Author "Della Longa S" Journal biochimica et biophysica acta
5 results on '"Della Longa S"'

1. Influence of allosteric effectors on the heme conformation of dromedary ferrous nitrosylhemoglobin detected by XANES spectroscopy

Author

Gino Amiconi, E. Burattini, Antonio Bianconi, Massimo Coletta, Roberto Santucci, Paolo Ascenzi, Stefano Della Longa, Mario Barteri, Agostina Congiu Castellano, CONGIU CASTELLANO, A, DELLA LONGA, S, Bianconi, A, Barteri, M, Burattini, E, Ascenzi, Paolo, Coletta, M, Santucci, R, and Amiconi, G.

Subjects
Hemeprotein, Camelus, Phytic Acid, Allosteric regulation, Biophysics, Analytical chemistry, Molecular Conformation, Heme, Ligands, Biochemistry, law.invention, chemistry.chemical_compound, Hemoglobins, Structural Biology, law, Animals, Clofibrate, Electron paramagnetic resonance, Spectroscopy, Molecular Biology, Histidine, Binding Sites, biology, Spectrum Analysis, Active site, XANES, Crystallography, chemistry, biology.protein
Abstract

The changes of the Fe heme-active site conformation of dromedary (Camelus dromedarius) nitrosylhemoglobin (HbNO) induced by inositol hexakisphosphate (IHP) and chlofibric acid (CFA) have been studied by using X-ray absorption near-edge structure (XANES) spectroscopy. Structural information has been determined by multiple scattering analysis of the Fe K-edge XANES spectra. The proximal histidine is found to move away from iron centers by about 0.4 Angstrom on the average over the four hemes upon binding of CFA or stoichiometric amount of IHP. In molar excess of polyanion or in the simultaneous presence of IHP, CFA and chloride, the proximal histidine moves back to a position very close to that observed in pure buffer; yet, the structure modulation induced by the allosteric effectors is not completely reversible. Such findings parallel with the functional properties and the spectroscopic (e.g., EPR and absorbance) characteristics of HbNO.

Published
1991

2. Iron site structure of two irreversible hemichromes from human hemoglobin, untreated and oxidized to sulfoxide at MetD6(55)beta.

Author

Della Longa S, Amiconi G, Artan Salah O, Ascone I, Barteri M, Bertollini A, Bianconi A, and Congiu Castellano A

Subjects
Binding Sites, Hemoglobin A metabolism, Humans, Iron chemistry, Methemoglobin analogs & derivatives, Oxidation-Reduction, Spectrum Analysis methods, Sulfoxides chemistry, X-Rays, Hemeproteins chemistry, Hemoglobin A chemistry, Methemoglobin chemistry
Abstract

The Fe K-edge X-ray absorption near-edge structure (XANES) spectra of two irreversible human hemichromes, spontaneously formed from HbA and HbMetSO (a hemoglobin derivative, where MetD6(55)beta has been previously oxidized to sulfoxide by chloramine T) were determined. The results show that the hemichrome from HbMetSO is characterized by the distal histidyl imidazole moved within the bonding distance of the heme iron. Such structure is different from that of the hemichrome spontaneously produced from native human hemoglobin, which probably has a hydroxide group as sixth heme ligand.

Published
1996
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3. Influence of allosteric effectors on the heme conformation of dromedary ferrous nitrosylhemoglobin detected by XANES spectroscopy.

Author

Congiu Castellano A, Della Longa S, Bianconi A, Barteri M, Burattini E, Ascenzi P, Coletta M, Santucci R, and Amiconi G

Subjects
Animals, Binding Sites, Camelus, Hemoglobins drug effects, Ligands, Molecular Conformation, Spectrum Analysis, Clofibrate pharmacology, Heme chemistry, Hemoglobins chemistry, Phytic Acid pharmacology
Abstract

The changes of the Fe heme-active site conformation of dromedary (Camelus dromedarius) nitrosylhemoglobin (HbNO) induced by inositol hexakisphosphate (IHP) and chlofibric acid (CFA) have been studied by using X-ray absorption near-edge structure (XANES) spectroscopy. Structural information has been determined by multiple scattering analysis of the Fe K-edge XANES spectra. The proximal histidine is found to move away from iron centers by about 0.4 Angstrom on the average over the four hemes upon binding of CFA or stoichiometric amount of IHP. In molar excess of polyanion or in the simultaneous presence of IHP, CFA and chloride, the proximal histidine moves back to a position very close to that observed in pure buffer; yet, the structure modulation induced by the allosteric effectors is not completely reversible. Such findings parallel with the functional properties and the spectroscopic (e.g., EPR and absorbance) characteristics of HbNO.

Published
1991
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4. Heterogeneity of the isolated subunits of the fetal and adult human hemoglobin in solution, detected by XANES spectroscopy.

Author

Congiu Castellano A, Castagnola M, Burattini E, Dell'Ariccia M, Della Longa S, Giovannelli A, Durham PJ, and Bianconi A

Subjects
Carbon Monoxide, Fetal Hemoglobin physiology, Hemoglobin A physiology, Humans, Molecular Structure, Oxygen, Spectrum Analysis methods, Structure-Activity Relationship, X-Rays, Fetal Hemoglobin analysis, Hemoglobin A analysis
Abstract

Differences in the local structure of the heme in the isolated alpha-, beta- and gamma-chains of the adult and fetal human hemoglobin are detected by XANES (X-ray absorption near-edge structure) spectroscopy. The ligand bonding angle to the iron ion in the ligated forms and the displacement of the Fe respect to the porphyrin plane in the deoxy forms are found to be different for each chain.

Published
1989
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5. Linear Fe-C-O configuration in carbonyl 1-methylimidazole iron(II) porphyrin detected by XANES in dispersive mode.

Author

Ascone I, Bianconi A, Dartyge E, Della Longa S, Fontaine A, and Momenteau M

Subjects
Imidazoles, Molecular Conformation, Solutions, X-Rays, Carbon, Carboxyhemoglobin, Iron, Metalloporphyrins, Oxygen, Spectrum Analysis
Abstract

The linear Fe-C-O configuration has been determined in the carbonyl 1-methylimidazole hindered iron(II) porphyrin derived from 'basket handle' complexes in which there are no constraints on the proximal imidazole. The structure at the iron site has been determined in toluene solution by fast measurements of XANES spectra, using the dispersive X-ray absorption method.

Published
1987
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