Local coordination geometry in Fe and Ca metalloproteins by XANES using synchrotron radiation. Bianconi, A. Inorganica Chimica Acta, 79:88, 1983.
Local coordination geometry in Fe and Ca metalloproteins by XANES using synchrotron radiation [link]Paper  doi  abstract   bibtex   
X-ray absorption spectroscopy using synchrotron radiation is opening new perspectives in the study of fundamental biological problems of structure and function of metalloproteins because of its unique capability to give direct structural information on the metal active sites of proteins in solution. The direct structural information in X-ray absorption spectra arise because of their interpretation in terms of electron scattering by neighbour atoms of the electrons photoemitted at the metal site. EXAFS oscillations arising from single scattering processes can give distances, coordination numbers and the type of neighbour atoms! A recent development on the X-ray absorption near edge structure: XANES [1] extending over about 50 eV energy range demonstrates that this part of the X-ray absorption spectrum also can be interpreted in terms of electron scattering by neighbour atoms. The spectra show strong multiple scattering resonances, like low energy electron spectroscopy, determined by atomic geometrical distribution of the neighbour atoms. The actual 'state of art' is such that after distance determination by EXAFS, XANES is able to distinguish between different possible geometrical structures [2]. We report XANES spectra of hemoglobin and related heme-proteins where we have found evidence of: In calcium proteins [4, 5] troponin-C and calmodulin [6] different orientations of COO − groups of aspartic and glutamic residues bound to Ca 2+ in the EF-hand loop can be distinguished and different sites are identified. The presence of the allosteric role of Mg 2+ , and the effects of drugs on calmodulin have been found.
@article{bianconi_local_1983,
	title = {Local coordination geometry in {Fe} and {Ca} metalloproteins by {XANES} using synchrotron radiation},
	volume = {79},
	issn = {00201693},
	url = {http://dx.doi.org/10.1016/s0020-1693(00)95120-x},
	doi = {10.1016/s0020-1693(00)95120-x},
	abstract = {X-ray absorption spectroscopy using synchrotron radiation is opening new perspectives in the study of fundamental biological problems of structure and function of metalloproteins because of its unique capability to give direct structural information on the metal active sites of proteins in solution. The direct structural information in X-ray absorption spectra arise because of their interpretation in terms of electron scattering by neighbour atoms of the electrons photoemitted at the metal site. EXAFS oscillations arising from single scattering processes can give distances, coordination numbers and the type of neighbour atoms! A recent development on the X-ray absorption near edge structure: XANES [1] extending over about 50 eV energy range demonstrates that this part of the X-ray absorption spectrum also can be interpreted in terms of electron scattering by neighbour atoms. The spectra show strong multiple scattering resonances, like low energy electron spectroscopy, determined by atomic geometrical distribution of the neighbour atoms. The actual 'state of art' is such that after distance determination by EXAFS, XANES is able to distinguish between different possible geometrical structures [2]. We report XANES spectra of hemoglobin and related heme-proteins where we have found evidence of: In calcium proteins [4, 5] troponin-C and calmodulin [6] different orientations of COO − groups of aspartic and glutamic residues bound to Ca 2+ in the EF-hand loop can be distinguished and different sites are identified. The presence of the allosteric role of Mg 2+ , and the effects of drugs on calmodulin have been found.},
	journal = {Inorganica Chimica Acta},
	author = {Bianconi, A.},
	year = {1983},
	keywords = {bio, ca, polymorphism, protein, xanes},
	pages = {88}
}

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