title: X-ray absorption fine-structure spectroscopy studies of Fe sites in natural human neuromelanin and synthetic analogues.
abstract: X-ray absorption fine-structure spectroscopy is used to study the local environment of the iron site in natural (human) neuromelanin extracted from substantia nigra tissue and in various synthetic neuromelanins. All the materials show Fe centered in a nearest neighbor sixfold (distorted) oxygen octahedron; the Fe-O distances, while slightly different in the natural and synthetic neuromelanin, are both approximately 2.0 A. Appreciable differences arise, however, in the second (and higher) coordination shells. In this case the synthetic melanin has the four planar oxygens bound to carbon rings with Fe-C distances of approximately 2.82 and 4.13 A; the human sample does not show the 2.82 A link but instead indicates a double shell at approximately 3.45 and 3.78 A.
authors.affiliation: Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556 USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Kropf
authors.forename: B A
authors.initials: BA
authors.lastname: Bunker
authors.forename: M
authors.initials: M
authors.lastname: Eisner
authors.forename: S C
authors.initials: SC
authors.lastname: Moss
authors.forename: L
authors.initials: L
authors.lastname: Zecca
authors.forename: A
authors.initials: A
authors.lastname: Stroppolo
authors.forename: P R
authors.initials: PR
authors.lastname: Crippa
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D002244:Carbon / Q000737:chemistry; D005583:Fourier Analysis; D006801:Humans; D066298:In Vitro Techniques; D007501:Iron / Q000737:chemistry; D008543:Melanins / Q000138:chemical synthesis / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D013057:Spectrum Analysis; D013378:Substantia Nigra / Q000737:chemistry; D014965:X-Rays
chemical_list: D008543:Melanins; C014121:neuromelanin; D002244:Carbon; D007501:Iron; D010100:Oxygen