Postnatal changes in subcellular distribution of copper,zinc and metallothionein in the liver of bank vole (Clethrionomys glareolus): a possible involvement of metallothionein and copper in cell proliferation

1. Dramatic interdependent changes in the intracellular concentrations of copper (Cu), zinc (Zn) and metallothionein (MT) in the liver of bank voles during the first 30 days of their life were observed.2. The post-mitochondrial Cu, Zn and MT (ZnMT) abruptly decreased between 1 and 3 days following birth but the nuclear MT (CuMT) and Cu increased at the same time, suggesting that Cu displaced Zn already bound to MT in the cytoplasm and subsequently the complex CuMT was translocated to the nuclei.3. The nuclear Cu concentration reached the highest level (62–71% of the total tissue Cu) in the period from day 3 to day 20 post-partum, just prior to and during a rapidly growing liver.4. The data indicate that MT and Cu may be involved in the hepatocyte proliferation.     

Immunoreactive CuSOD and MnSOD in lymphocytes sub-populations from normal and trisomy 21 subjects according to age

Copper and manganese superoxide dismutases (CuSOD and MnSOD) were measured by radioimmunoassay in B and T lymphocytes and macrophages, in patients with trisomy 21 and in matched controls. In the controls, CuSOD was present in greater amounts than MnSOD and there were quantitative differences in the distribution in the three cellular sub-populations. In trisomy 21, levels of CuSOD were raised, with no change in levels of MnSOD, supporting the theory of a gene dosage effect.There were significant positive and negative correlations between age and CuSOD levels in controls, and a correlation approaching significance for MnSOD. In trisomy 21, there was no correlation between age and CuSOD levels, and the only significant correlation for MnSOD was for B lymphocytes.     

Synthesis and structure of μ-3,3′-[ 1,2-ethanediyl-bis(nitrilomethylidyne)-bis(2-hydroxybenzoato)] aquadicopper(II) hydrate

The complex μ-3,3′-[1,2-ethanediyl-bis(nitrilome- thylidyne)-bis(2-hydroxybenzoato)] aquadicopper(II) hydrate, C₁₈H₁₆N₂O₈Cu₂, was isolated from an attempted preparation of a copper lanthanum binuclear complex. The dark purple crystals are monoclinic, space group P2₁/n, with 4 molecules per unit cell; dimensions a = 13.961(5), b = tl.787(3), c = 11.622(3) Å and β = 113.09(2)°. The final R was 0.046 for the 2062 reflections used in the analysis. The Cu atom in the N₂O₂ cavity is five coordinate with CuN distances of 1.879 and 1.880 Å and CuO distances of 1.898 and 1.900 Å. A water molecule at 2.557 Å completes the square pyramidal arrangement. The second Cu in the O₄ cavity is square planar, with CuO distances to the bridging oxygens of 1.914 and 1.909 Å and to the carboxy oxygens of 1.871 and 1.882 Å. A survey of copper complexes in a square planar N₂O₂ arrangement has led to the equation δCu from the N₂O₂ plane = 0.822 – 0.275 (CuO axial distance) with a correlation coefficient of 0.98 for the 12 structures in which the Cu atom is bonded to a fifth oxygen atom. A model for the transition from square planar to square pyramidal geometry is proposed.     

Strong and symmetric halogen bonding in coordination compounds of carboxylic acid derivatives; the crystal structure of (3,6-dithiaoctanedioato-S,S′-(3,6-dithiaoctanedioic acid-S,S′)-copper(I) redetermined at 173 K

3,6-dithianoctanedioic acid forms a Cu(I) compound in which electrical neutrality is achieved by elaborate hydrogen bonding and sharing on protons. The title compund crystallizes in the monoclinic space group P2/n with Z = 2. Unit-cell parameters are a = 11.625(2), b = 7.664(1), c = 9.874(2) Å, β = 95.16°, D_m = 1.80(2), D_c = 1.83 g cm^?3. The structure was solved by means of standard direct methods and refined with full-matrix least-squares techniques to an R-value of 0.026 (R_w = 0.042). The Cu(I) ion is tetrahedrally coordinated by four thioether S-atoms (CuS = 2.29–2.33 Å). The molecules are linked by very strong hydrogen bonds between non-coordinating carboxylate groups in such a way that the average number of acidic hydrogens per molecule is three. One of these hydrogens lies on a twofold axis and forms a short symmetrical hydrogen bond, with a OO distance of 2.441(2) Å. Unusual features in the infrared spectrum of this compund can be interpreted on the basis of the observed crystal structure.     

Nucleophilic addition and various species formed in the Cu(II)NCO−3(5)-methylpyrazole system

From the Cu(II)NCO⁻3(5)-methylpyrazole (mpz) system two compounds Cu(NCO)₂(mpz)₂ and four compounds Cu(mpz·NCO)₂ were isolated. The latter compounds contain carbamoylmethylpyrazolate anions as chelate ligands and are coligand isomers of the cyanate compounds. According to the results of indirect structural methods, the Cu(NCO)₂(mpz)₂ complexes have pseudooctahedral structures and differ in their polyhedron distortions. The Cu(mpz·NCO)₂ complexes show tetragonally distorted six or five coordinate structures, possibly differing also by the methyl group position on the pyrazole ring.     

Preparation and structural characterization of di-μ-azido-bis[azido(2-aminopyridine)aquo]dicopper(II), [Cu(2-ampy)(N3)2(H2O)]2

Di-μ-azido-bis[azido(2-aminopyridine)aquo]dicopper(II), [Cu(2-ampy)(N₃)₂(H₂O)]₂, was synthesized and characterized by X-ray crystallography. The crystals are triclinic, space group P$\text{1}$, with a = 7.142(1), b = 7.812(1), c = 9.727(1) Å, a = 96.52(1), β = 95.52(1), γ = 113.47(1)°, and Z = 1. The structure was refined to R_F = 0.030 for 1960 observed MoKα diffractometer data. The dimeric molecule, which possesses a crystallographic inversion center, contains both terminal and μ(1)-bridging azido groups. Each copper(II) atom is further coordinated by a 2-aminopyridine ligand (via its ring N atom) and a water molecule to give a distorted square pyramid, with the metal atom raised by 0.17 Å above the N₄ basal plane [CuN (ring) = 2.001(2), CuN (azide) = 1.962(3)–2.018(2) Å] towards the apical aquo ligand [CuO = 2.371(2) Å]. Each water molecule forms an intramolecular O?HN (amine) acceptor hydrogen bond, and is linked by two OH?N (terminal azide) intermolecular donor hydrogen bonds to adjacent dimeric complexes to yield a layer structure parallel to (001). Infrared and electronic spectral data are presented and discussed.     

Characterization of a mononuclear copper carboxylate complex: Bis(acetylsalicylato)bis(pyridine)copper(II)

The preparation, spectral properties, and crystal structure of a mononuclear copper(II) complex of acetylsalicylate and pyridine are reported. The complex exists as bis(acetylsalicylato)bis(pyridine)copper(II) both in the solid state and in chloroform solution. The crystal is monoclinic, space group P2₁/n, with a = 17.823(5), b = 10.903(4), c = 6.598(2) Å, β = 95.74(2)°. The final refinement used 1472 observed reflections and gave an R of 0.046. The copper atom is surrounded by four atoms in a trans square planar arrangement with two short CuO distances of 1.949(3) Å and two CuN distances of 2.003(4) Å. Two longer CuO distances of 2.623(3) Å are made with the remaining oxygen atoms of the aspirin carboxylate groups.     

Copper reduction in a pilot-scale membrane-free bioelectrochemical reactor

A pilot-scale, membrane-free, bioelectrochemical system (BES) reactor (16L in volume) installed by five cathodes with different distance to anode was tested for the removal of copper. CuSO4 solution was used as catholyte and anaerobic microorganisms grew as anodic biocatalyst. In the reactor, Cu(II) was reduced and recovered as solid-state copper deposits on cathodes accompanied with power production. When 600 and 2000 mg of Cu2+ were added into the cathode chamber, removal efficiency of 92% over 480 h and 48% over 672 h period with electric quantities of 2724 C and 8703 C, and cathodic efficiencies of 61.92% and 45.60% were achieved, respectively. The reduction reaction rate depended on the initial average Cu2+ concentration. The internal resistance decreased and voltage output increased as the distance of each cathode to anode decreased. The mass of metal Cu crystals and Cu(I) compounds deposited on each cathode was dependent on current intensity.     

Peroxidation of lysozyme treated with Cu(II) and hydrogen peroxide

When lysozyme was treated with Cu(II) and H₂O₂ at pH 7.4, the protein underwent polymerization as well as changes in its fluorescent characteristics. Upon prolonged incubation, most of the protein aggregates were degraded into smaller peptides. Amino acid analysis indicated that the basic amino acid residues were most susceptible to the oxidation. Tryptophan residues were converted to N-formylkynurenine and kynurenine, and lysine residues were deaminated to form α-aminoadipic acid δ-semi- aldehyde. During Cu(II)H₂O₂ treatment, the formation of carbonyl groups was accompanied by the loss of free amino groups in the protein. Succinylation of free amino groups protected lysine residues from oxidation by Cu(II)H₂O₂, but failed to prevent polymerization. The studies with the modified lysozyme suggest that Cu(II)H₂O₂ can oxidize various amino acid residues in addition to lysine to generate different types of carbonyl compounds and these carbonyl compounds may be responsible for the formation of crosslinks in the polymerization process.     

Binuclear metal complexes. 59. Synthesis and magnetism of dicopper(II) and copper(II)-nickel(II) complexes with N,N′-ethylenedisalicylamidatocuprate(II)

The complexes [Cu(samen)Cu(L)] and [Cu(samen)Ni(L)₂] (Lbpy, phen) have been synthesized by the reaction of sodium N,N′-ethylenedisalicylamidatocuprate(II) pentahydrate (Na₂- [Cu(samen)]·5H₂O), a divalent metal ion, and 2,2′- dipyridyl or 1,10-phenanthroline. Cryomagnetic data for the CuCu complexes did not fit the Bleaney- Bowers equation; but the data did fit a modified Bleaney-Bowers equation

with a large negative J and a significant negative θ, suggesting that a considerable magnetic interaction operates between essentially planar [Cu(samen)Cu(L)] molecules. The magnetisms of the CuNi complexes were well interpreted in terms of the susceptibility equation based on the Heisenberg model. An antiferromagnetic spin-exchange interaction (J= −13∼−14 cm⁻¹) was suggested between the metal ions.     

The structure of silver(I) iodide and bromide,and the silver(I) solvate in tetrahydrothiophene solution: An X-ray scattering and raman spectroscopic study

Structures of silver(I) iodide and bromide, and the solvated silver(I) ion are determined in tetrahydrothiophene solution with Large Angle X-ray Scattering (LAXS) technique. In a silver(I) perchlorate tetrahydrothiophene solution, silver(I) is solvated by four tetrahydrothiophene molecules in a regular tetrahedron. The main peak in the radial distribution function corresponds to four AgS distances at 2.526(7) Å. An SS distance at 2.65(2) Å in the solvent bulk is also included in the main peak. This shows that an internal structure exists in the tetrahydrothiophene bulk. Silver(I) iodide and bromide are tetrameric complexes with a stella quadrangula configuration, in saturated solution. The distances in the [AgI(SC₄H₈)]₄ complex are AgI 2.799(4); AgAg, 3.072(6) and II, 4.638(19) Å and in the [AgBr(SC₄H₈)]₄ complex they are AgBr, 2.592(3); AgAg, 2.866(5) and BrBr, 4.25(4) Å. The AgI bond distances in the [AgI(SC₄H₈)]₄ complex is shorter in solution than in the solid solvate. This is because bulk tetrahydrothiophene is a markedly weaker donor than free tetrahydrothiophene due to the sulfursulfur interactions in the bulk, shown to be around 2.65 Å. Raman spectroscopic studies on silver(I) and copper(I) iodide and silver(I) chloride tetrahydrothiophene solutions show that the polymetric structures predominate in concentrated solution and that they disintegrate upon dilution.     

On the structure of Hg2I3+ in dimethylsulfoxide and aqueous solution. An X-ray scattering and raman spectroscopic study

Dimethylsulfoxide and aqueous solutions of mercury(II) in large excess over iodide have been investigated by X-ray scattering techniques supported by Raman spectroscopic measurements. The composition of the solutions has been selected to ensure that the cationic complex Hg₂I³⁺ is the predominant iodide species. The structure parameters of the solvated Hg₂I³⁺ ion have been refined by a least- squares procedure on the scattering data, using known structural parameters for the additional molecular entities present. The Hg₂I³⁺ entity is more or less identical in DMSO and water. The HgI bond distance is 2.613(12) and 2.632(5) Å and the HgHg distance is 3.66(5) and 3.70(1) Å in DMSO and water, respectively. This yields a HgIHg angle of 89° in both solvents. The mercury(II) atom in this complex is most probably solvated in a tetrahedral fashion by three DMSO or H₂O molecules. The structure of Hg₂I³⁺ is discussed in the light of recent results for the Ag₄I³⁺ complex in solution and relevant crystal structures.     

Crystal and molecular structure of [N,N′-ethylenebis(methyl-2-amino-1-cyclopentenedithiocarboxylato)]copper(II): A quantitative relationship between tetrahedral distortion and redox potentials in copper N2S2 compounds and the relevance to type I copper(II) centers

The crystal and molecular structure of the copper(II) complex of the N₂S₂ tetradentate ligand, ethylenebis(methyl-2-amino-1-cyclopentenedithiocarboxylate), was solved at room temperature by a single crystal x-ray diffraction study. The complex crystallizes in the orthorhombic space group P2₁2₁2₁ with a = 7.739(1) Å, b = 13.893(2) Å, c = 17.096(3) Å, V = 1838(1) ų, ?_observed = 1.56 g cm^?3 and ?_calculated = 1.57 g cm^?3 for a molecular weight of 434.2, and Z = 4. Diffraction data were collected with a Syntex P$\text{1}$ diffractometer using graphite-monochromatized Cu (λ = 1.5418 Å) radiation. The heavy atoms were located from a Patterson synthesis; all other nonhydrogen atoms were located using difference Fourier techniques, and hydrogen atoms were placed in calculated positions. Final refinement resulted in discrepancy indices of R = 0.067 and goodness of fit of 2.92 for all 995 reflections (5° < 2θ < 100°) greater than three times their standard deviation. The molecules are monomeric and well separated. Bond distances in the two ”halvesldquo; of the ligand are sufficiently different to suggest that different resonance structures exist in each portion. This agrees with the rhombic symmetry displayed by the frozen glass esr spectrum of the compound (_xx ≠ g_yy). The dihedral angle between the planes defined by the CuN₂ and CuS₂ planes is 20.0°, indicating a rather distorted inner coordination sphere. The copper(II)-copper(I) reduction potentials found for this compound and the trimethylene and tetramethylene analogs were determined to be ?1.01, ?0.79, and ?0.64 V respectively. A quantitative relationship between tetrahedral distortion and redox potentials is obtained, and these results are discussed in terms of ”blueldquo; copper(II) sites in proteins. Trends in CuS and CuN bonding patterns in the same three compounds are discussed with regard to the short CuS (cys) bond distance in plastocyani Finally, a brief discussion of the optical spectra of these three compounds, their variation, and their significance with respect to tetrahedral symmetry in copper(II) protein sites is presented.     

A novel binuclear [CuSMo] cluster at the active site of carbon monoxide dehydrogenase: characterization by X-ray absorption spectroscopy

The structurally characterized molybdoenzyme carbon monoxide dehydrogenase (CODH) catalyzes the oxidation of CO to CO2 in the aerobic bacterium Oligotropha carboxidovorans. The active site of the enzyme was studied by Mo- and Cu-K-edge X-ray absorption spectroscopy. This revealed a bimetallic [Cu(I)SMo(VI)(double bond O)2] cluster in oxidized CODH which was converted into a [Cu(I)SMo(IV)(double bond O)OH2] cluster upon reduction. The Cu...Mo distance is 3.70 A in the oxidized form and is increased to 4.23 A upon reduction. The bacteria contain CODH species with the complete and functional bimetallic cluster along with enzyme species deficient in Cu and/or bridging S. The latter are precursors in the posttranslational biosynthesis of the metal cluster. Cu-deficient CODH is the most prominent precursor and contains a [HSMo(double bond O)OH2] cluster. Se-K-edge X-ray absorption spectroscopy demonstrates that Se is coordinated by two C atoms at 1.94-1.95 A distance. This is interpreted as a replacement of the S in methionine residues. In contrast to a previous report [Dobbek, H., Gremer, L., Meyer, O., and Huber, R. (1999) Proc. Natl. Acad. Sci. U.S.A. 96, 8884-8889] Se was not identified in the active site of CODH.     

X-ray absorption studies of the Cu-dependent phenylalanine hydroxylase from Chromobacterium violaceum. Comparison of the copper coordination in oxidized and dithionite-reduced enzymes.

The coordination chemistry of the Cu sites of phenylalanine hydroxylase (PAH) from Chromobacterium violaceum has been studied by X-ray absorption spectroscopy (XAS). The EXAFS of the Cu(II) form of the enzyme resembles that of other non-blue copper proteins such as plasma amine oxidases and dopamine-beta-hydroxylase and is characteristic of a mixed N/O coordination shell containing histidine ligation. Detailed simulations of the raw EXAFS data have been carried out using full curved-wave restrained refinement methodologies which allow imidazole ligands to be treated as structural units. The results suggest a Cu(II) coordination of two histidines and two additional O/N-donor groups. A reasonable fit to both data sets can be obtained by assuming that the non-imidazole first-shell donor atoms are derived from solvent (H2O or OH-). The EXAFS of the reduced enzyme shows major differences. The amplitude of the first shell in the Fourier transform is only 50% of that of the oxidized enzyme, indicative of a substantial reduction in coordination number. In addition, the first shell of the transform is split into two components. Simulations of the reduced data can be obtained by either two histidines at a long distance of 2.08 A and an O ligand at a short distance of 1.88 A or two histidines at a short distance of 1.90 A and one second-row scatterer such as S or Cl at 2.20 A. Comparison of absorption edge data on the reduced enzyme with data from Cu(I) bis- and tris(1,2-dimethylimidazole) complexes suggests a pseudo-three-coordinate structure.     

The synthesis of technetium(V) complexes containing sterically bulky thiolate ligands. The molecular structure of tetrabutylammonium oxotetrakis(2,4,6-trimethylbenzenethiolato)technetate(V)

The reactions between [TcOCl₄]⁻ and the sterically bulky thiols ArSH (Ar = 2,4,6-Me₃C₆H₂, 2,4,6- Prⁱ₃C₆H₂ and 2,6-Ph₂C₆H₃) in methanol afford complexes of formula [TcO(SAr)₄]⁻ which may be isolated as salts with bulky organic cations. The molecular structure of [Buⁿ₄N][TcO(2,4,6-Me₃C₆H₂S)₄] was determined by X-ray diffraction methods. The Tc(V) centre was found to adopt the expected square pyramidal geometry in which an oxo group occupies the apical site and the four thiolate sulphurs the basal sites. The TcO distance is 1.659(11) Å and the average TcS distance 2.38(2) Å. The average cis STcS, trans STcS and OTcS angles are respectively 82.7(6)°, 138.4(3)° and 110.8(4)°.     

Biogenic monoamine levels in the central nervous system of the sea hare,Aplysia kurodai

1. By using a three-dimensional-coulometric HPLC system, biogenic monoamines and their metabolites were quantified simultaneously in the central nervous system of the sea hare, Aplysia kurodai.2. Precursor amino acids, tyrosine-4 (TYR-4) and tryptophan (TRP), and dopamine (DA), 3, 4-dihydroxyphenylacetic acid (DOPAC) and 5-hydroxytryptamine (5-HT) were detected in all the ganglia examined.3. Levels of these compounds in the cerebral, pedal and parieto-visceral ganglia were higher than those of the other ganglia examined.4. In some ganglia, epinephrine (E), 3-O-methyldopa (30MD), 3-methoxytyramine (3-MT), dihydroxyphenylethleneglycol (DOPEG), metanephrine (MN), vanillic acid (VA), octopamine (OCT), kynurenine (KYN) and 5-hydroxyindoleacetic acid (5-HIAA) were also detected.5. The main metabolic pathways of biogenic monoamines were shown to be TYR-4DADOPAC and TRP5-HT5-HIAA. Furthermore, following five pathways were also suggested to be present; TYR-4DAEMNVA, TYR-4TYRAOCT, TYR-43OMD, DA3-MT. EDOPEG and TRPKYN.     

Luminescence decay from copper(I) complexes of metallothionein

Luminescence in the 600 nm region from aqueous solutions of Zn₇metallothionein (ZnMT) has been studied as a function of the extent of substitution of the ZnMT with Cu⁺. The steady state emission intensity shows a strong correlation with cluster formation. Analysis of the emission decay curves obtained by single photon-counting techniques using a multiexponential decay function, indicates that three components are responsible for the observed emission intensity. A short lived component exhibits a lifetime of 20 ns, while the two longer lived components exhibit lifetimes in the 1 μ range at room temperature. The longer-lived emission is assigned to the excited triplet states of the CuS chromophore, most probably the metal-centered 3d⁹4s¹.     

EPR and magnetic studies of copper amino carboxylates

Metal complexes of N-substituted amino acids provide simple but appropriate model compounds for the understanding of metal protein interactions. Seven complexes of copper viz. Cu(II) N-acetyl glycinate mono-hydrate, Cu(II) N-acetyl methioninate, Cu(II) N-acetyl alaninate, Cu(II) N-acetyl valinate, Cu(II) N-acetyl glutamate, Cu(II) cyanoacetate, and Cu(II) thio-dipropionate, have been investigated by EPR measurements. The spectra appear to arise from dimeric coppers (s=1) coupled by anti-ferromagnetic exchange. The exchange coupling constant ‘2J’ and the CuCu separation ‘r’ have been evaluated from the spectral data. Although the existence of bridged structure is confirmed, super-exchange via the ligands appears to be the dominant mechanism. All of these complexes exist as monomers in strongly coordinating solvents.     

Synthesis,structural characterization,and properties of the organothorium alkylthiolate complex [(CH3)5C5]2Th(SCH2CH2CH3)2

This contribution reports the synthesis and characterization of the organothorium alkylthiolate complex [(CH₃)₅C₅]₂Th(SCH₂CH₂CH₃)₂. This compound crystallizes in the monoclinic space group C2/c (#15) with four molecules in a cell of dimensions a=19.066(2), b=11.603(1), c=16.379(2) Å, and β=130.08(1)°. Least-squares refinement led to a value for the conventional R index (on F_o) of 0.040 for 132 variables and 2030 observations having F_o²⩾3σ(F_o²). The molecular structure consists of an unexceptional ‘bent sandwich’ [(CH₃)₅C₅]₂Th fragment coordinated to two n-propylthiolate ligands. The ThS bond distance is 2.718(3) Å; the SC(α) distance, 1.78(2) Å; the ThSC(α) angle, 108.3(5)°; and the SThS′ angle, 102.5(2)°. Contrasts are drawn with the structures of analogous actinide alkoxides