scholarly journals An extended-X-ray-absorption-fine-structure study of bovine erythrocyte superoxide dismutase in aqueous solution. Direct evidence for three-co-ordinate Cu(I) in reduced enzyme

1984 ◽  
Vol 219 (3) ◽  
pp. 985-990 ◽  
Author(s):  
N J Blackburn ◽  
S S Hasnain ◽  
N Binsted ◽  
G P Diakun ◽  
C D Garner ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Superoxide Dismutase ◽  
Structure Study ◽  
Reduced Form ◽  
Edge Structure ◽  
X Ray ◽  
Absorption Fine ◽  
Copper Site ◽  
Erythrocyte Superoxide Dismutase ◽  
X Ray Absorption

Copper and zinc K-edge e.x.a.f.s. (extended X-ray-absorption fine structures) were measured for the metal sites of oxidized and reduced bovine superoxide dismutase in aqueous solution. Detailed analysis of the spectra indicates that the copper site of the enzyme changes on reduction and is most probably co-ordinated to three imidazole groups at a shorter distance Cu-N(alpha) = 0.194 nm (1.94 A) in the reduced form compared with a co-ordination of four imidazole groups at 0.199 nm (1.99 A) and an oxygen atom from solvent water at 0.224 nm (2.24 A) in the oxidized form. Examination of the edge, near-edge structure and e.x.a.f.s. of the zinc sites indicates that the stereochemical changes at copper that accompany reduction introduce minimal perturbation on the stereochemistry at zinc.

scholarly journals Direct structural information for the copper site of dopamine β-mono-oxygenase obtained by using extended X-ray-absorption fine structure

1984 ◽  
Vol 221 (2) ◽  
pp. 545-548 ◽  
Author(s):  
S S Hasnain ◽  
G P Diakun ◽  
P F Knowles ◽  
N Binsted ◽  
C D Garner ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Superoxide Dismutase ◽  
Fine Structure ◽  
Structural Information ◽  
Bovine Erythrocyte ◽  
X Ray ◽  
Absorption Fine ◽  
Copper Site ◽  
Erythrocyte Superoxide Dismutase ◽  
X Ray Absorption

Copper K-edge e.x.a.f.s (extended X-ray-absorption fine structure) was measured for dopamine beta-mono-oxygenase in aqueous solution. Comparison with the Cu K-edge e.x.a.f.s. of bovine erythrocyte superoxide dismutase shows a close resemblance. Detailed analysis of the e.x.a.f.s. indicates that the copper atom is bound to four imidazole groups at 0.201 nm with one or two oxygen atoms at 0.23 nm.

scholarly journals An extended X-ray-absorption-fine-structure study of the copper and zinc sites of freeze-dried bovine superoxide dismutase

1983 ◽  
Vol 213 (3) ◽  
pp. 765-768 ◽  
Author(s):  
N J Blackburn ◽  
S S Hasnain ◽  
G P Diakun ◽  
P F Knowles ◽  
N Binsted ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Structure Study ◽  
X Ray ◽  
Absorption Fine ◽  
Copper And Zinc ◽  
Freeze Dried ◽  
Copper Site ◽  
Detailed Simulation ◽  
X Ray Absorption ◽  
Best Fit

Copper and zinc K-edge-extended X-ray-absorption fine structures were measured for the metal sites of freeze-dried bovine superoxide dismutase and the model compounds tetrakis(imidazole)cupric nitrate and tetrakis(imidazole)zinc perchlorate. Detailed simulation of the spectra indicates that the copper site of the enzyme is best fit by co-ordination of four imidazole groups with Cu-N(alpha) distances of 0.198 nm (1.98 A). The zinc site is best fit by three imidazole groups at 0.201 nm (2.01 A) and an oxygen (from aspartate) at 0.203 nm (2.03 A).

Fluorescence Extended X-Ray Absorption Fine Structure Study on Local Structures of Rare-Earth-Doped InGaGdN

2016 ◽  
Vol 1133 ◽  
pp. 429-433
Author(s):  
Siti Nooraya Mohd Tawil ◽  
Shuichi Emura ◽  
Daivasigamani Krishnamurthy ◽  
Hajime Asahi
Keyword(s):  
Fine Structure ◽  
Rare Earth ◽  
Nearest Neighbor ◽  
Structure Study ◽  
Edge Structure ◽  
X Ray ◽  
Local Structures ◽  
Absorption Fine ◽  
X Ray Absorption

Local structures around gadolinium atoms in rare-earth (RE)-doped InGaGdN thin films were studied by means of fluorescence extended X-ray absorption fine structure (EXAFS) measured at the Gd LIII-edges. The samples were doped with Gd in-situ during growth by plasma-assisted molecular beam epitaxy (PAMBE). Gd LIII-edge EXAFS signal from the GaGdN, GdN and Gd foil were also measured as reference. The X-ray absorption near edge structure (XANES) spectra around Gd LIII absorption edge of InGaGdN samples observed at room temperature indicated the enhancement of intensities with the increase of Gd composition. Further EXAFS analysis inferred that the Gd atoms in InGaN were surrounded by similar atomic shells as in the case of GaGdN with the evidence indicating majority of Gd atoms substituted into Ga sites of InGaGdN. A slight elongation of bond length for the 2nd nearest-neighbor (Gd–Ga) of sample with higher Gd concentration was also observed.

Effect of the ligand in the crystal structure of zinc oxide: an x-ray powder diffraction, x-ray absorption near-edge structure, and an extended x-ray absorption fine structure study

2016 ◽  
Vol 6 (2) ◽  
pp. 93-97
Author(s):  
María de los A. Cepeda-Pérez ◽  
Cristina M. Reyes-Marte ◽  
Valerie Ann Carrasquillo ◽  
William A. Muñiz ◽  
Edgar J. Trujillo ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Zinc Oxide ◽  
Fine Structure ◽  
Powder Diffraction ◽  
Structure Study ◽  
Edge Structure ◽  
X Ray ◽  
Absorption Fine ◽  
Image Position ◽  
X Ray Absorption

Abstract

Manganese K- and L3-Edge X-Ray Absorption Fine Structure Study of Zn1-xMnxTe

2013 ◽  
Vol 634-638 ◽  
pp. 2489-2492 ◽  
Author(s):  
Wei Zheng ◽  
Ling Yun Jang ◽  
Jenn Min Lee ◽  
Rui Sheng Zheng ◽  
Chee Wee Liu ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Fine Structure ◽  
Structure Study ◽  
Chemical Bonds ◽  
Bulk Materials ◽  
Absorption Data ◽  
Edge Structure ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption

High-resolution synchrotron radiation x-ray absorption data on Mn K- and L3-edge for semimagnetic semiconductor Zn1-xMnxTe bulk materials are presented. A detailed analysis of the extended x-ray absorption fine structure by using the IFEFFIT program, and the chemical bonds of Mn-Te are obtained. The x-ray absorption near-edge structure of the Mn K- and L3-edges are investigated, and the electronic structure of Zn1-xMnxTe with various compositions are studied.

scholarly journals An extended-X-ray-absorption-fine-structure study of freeze-dried and solution ovotransferrin. Evidence for water co-ordination at the metal-binding sites

1987 ◽  
Vol 247 (2) ◽  
pp. 369-375 ◽  
Author(s):  
S S Hasnain ◽  
R W Evans ◽  
R C Garratt ◽  
P F Lindley
Keyword(s):  
Fine Structure ◽  
Metal Binding ◽  
Binding Sites ◽  
Structure Study ◽  
Humid Atmosphere ◽  
Edge Structure ◽  
X Ray ◽  
Absorption Fine ◽  
Freeze Dried ◽  
X Ray Absorption

Our previous extended-X-ray-absorption-fine-structure (e.x.a.f.s.) study has shown that the probable iron environment in chicken ovotransferrin involves two low-Z ligands (consistent with phenolate linkages) at 0.185(1) nm and four low-Z ligands at 0.204(1) nm [Garratt, Evans, Hasnain & Lindley (1986) Biochem. J. 233, 479-484]. Herein we provide additional information from the e.x.a.f.s. and near-edge structure suggestive of a decrease in the co-ordination number of ovotransferrin-bound iron upon freeze-drying. These effects are reversible, and exposure of the freeze-dried material to a humid atmosphere results in reversion to the solution spectra. Progressive rehydration was monitored by using e.p.r. spectroscopy and was confirmed by recording the high-resolution X-ray-absorption near-edge structure (x.a.n.e.s.). The results suggest the presence of a labile water molecule at the iron-binding sites of ovotransferrin in solution.

Structure study of the chalcogens and chalcogenides by X-ray absorption fine structure

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Hiroyuki Ikemoto ◽  
Takafumi Miyanaga
Keyword(s):  
Fine Structure ◽  
Covalent Bond ◽  
Narrow Channel ◽  
Structure Study ◽  
Chain Structure ◽  
Covalent Bonds ◽  
X Ray ◽  
Absorption Fine ◽  
Amorphous States ◽  
X Ray Absorption

AbstractIn this review, we make a survey of the structure studies for the chalcogen elements and several chalcogenides in liquid, amorphous and nanosized state by using X-ray absorption fine structure (XAFS). The chalcogen elements have hierarchic structures; the chain structure constructed with the strong covalent bond as a primary structure, and the weaker interaction between chains as a secondary one. Existence of these two kinds of interactions induces exotic behaviors in the liquid, amorphous and nanosized state of the chalcogen and chalcogenides. XAFS is a powerful structure analysis technique for multi-element systems and the disordered materials, so it is suitable for the study of such as liquid, amorphous and nanosized mixtures. In section 2, the structures for the liquid state are discussed, which show the interesting semiconductor-metal transition depending on their temperatures and components. In section 3, the structure for the amorphous states are discussed. Especially, some of chalcogens and chalcogenides present the photostructural change, which is important industrial application. In section 4, the structures of nanosized state, nanoparticles and isolated chain confined into the narrow channel, are discussed. The studies of the nanoparticle and the isolated chain reveal the alternative role between the intrachain covalent bonds and the interchain interaction.

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