- Copper2+ Binding to α-Synuclein. Histidine50 Can Form a Ternary Complex with Cu2+ at the N-Terminus but Not a Macrochelate
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α-Synuclein (αSyn) forms amyloid fibrils in the neurons of Parkinson's disease (PD) patients'. Despite a role for Cu2+ in accelerating αSyn fibril formation, coupled with reports of copper dis-homeostasis in PD, there remain controversies surrounding the coordination geometry of Cu2+ with αSyn. Here we compare visible circular dichroism (CD) spectra of Cu2+ loaded on to full-length αSyn together with four peptides that model aspects of Cu2+ binding to the N-Terminus and histidine50 of αSyn. With glycine as a competitive ligand, the affinity of Cu2+ for full-length αSyn is determined to have a conditional dissociation constant, at pH 7.4, of 0.1 nM. A similar affinity of 0.3 nM is determined for the tripeptide Met-Asp-Val(MDV) that mimics the N-Terminus of αSyn, while the incorporation of a putative histidine side chain in the N-Terminal complex facilitates the formation of a macrochelate with the histidine, which results in an increase in the affinity for Cu2+ to 0.03 nM at pH 7.4. Comparisons of the visible absorbance and CD spectra over a range of pH values also indicates that the MDV tripeptide closely models Cu2+ binding to full-length αSyn and rules out a role for His50 in the primary Cu2+ binding complex of monomeric αSyn. However, there are reports that suggest His50 does form a macrochelate with the N-Terminal Cu2+ complex; we reconcile these conflicting observations by identifying a concentration dependence of the interaction. Only at the higher concentrations can the imidazole nitrogen bind to the N-Terminal Cu2+ to form a ternary complex rather than via a macrochelate. This work shows even for this intrinsically disordered protein a large macrochelate with Cu2+ is not favored. Understanding Cu2+ coordination to αSyn gives a more complete picture of its place in amyloid assembly and cytotoxicity.
- Tian, Yao,Stanyon, Helen F.,Barritt, Joseph D,Mayet, Uroosa,Patel, Pelak,Karamani, Elena,Fusco, Giuliana,Viles, John H.
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- 2H magic-angle spinning NMR and powder diffraction study of deuterated paramagnetic copper(II) glycinato complexes. Information on crystallographic symmetries, stereo-isomerism, and molecular mobility available from ssNMR spectra
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Effects of stereochemistry, polymorphism, crystal packing, and solid phase mobility on the 2H magic-angle spinning (MAS) NMR spectra of the paramagnetic Cu(II) glycinato complexes have been investigated. The reliability of information obtained from the spectra, such as symmetry relations within a molecule, number of chemical sites or molecules found in the asymmetric units, was confirmed by previously published X-ray crystal and molecular structures. From the 2H MAS spectra, complemented with powder diffractograms of the synthetized bis(glycinato-d4)copper(II) complexes, we could identify three solid phases, namely the cis aqua and non-aqua forms and the trans non-aqua crystals. A fourth sample was identified as octahedral copper(II) complex chain with bidentate glycine and NO3 ligands in the octahedral building units. Correlations between the sign and magnitude of the observed paramagnetic shifts and the number of bonds and/or the dihedral angles connecting the actual 2H nucleus and the paramagnetic center, useful in structural assignments, were revealed. The agreement of the 2H MAS NMR spectral information with the available crystal diffraction data forecast their applicability in NMR crystallographic works too.
- Szalontai, Gábor,Csonka, Róbert,Kaizer, József,Bombicz, Petra,Sabolovi?, Jasmina
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- Copper complex of glycine Schiff base: In situ ligand synthesis, structure, spectral, and thermal properties
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The novel glycine Schiff base copper complex, [Cu(C7H 6NO3)2(H2O)]·0.5H 2O, has been prepared by the in situ ligand synthesis method. The compound has been characterised by solid state IR a
- Trzesowska-Kruszynska, Agata
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- Ligand Decomposition in the Photolysis of Copper(II)-Amino-acid Complexes in Aqueous Solution
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Ligand decomposition following charge-transfer excitation of bis(glycinato)cuprate(II) in aqueous solution gives NH3 and HCHO as the final products in yields equivalent to the reduction of the metal Cu(I).An intermediate, observed by flash photolysis, is
- Das, Suresh,Johnson, G. R. Alastair,Nazhat, Najdat B.,Saadalla-Nazhat, Rajiha
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- ENERGY-EFFICIENT SOLVENT-FREE METHOD FOR PRODUCING METAL CHELATES
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The invention relates to a method for producing, amongst other things, amino-acid and/or hydroxycarboxylic-acid metal chelates, a solvent-free mixture of at least one metal oxide, metal hydroxide, metal carbonate or oxalate, and the solid organic acid is subjected to intensive mechanical stress. According to the invention, this is done in that the reaction partners are introduced in particle form into a fluid stream of a fluid-bed countercurrent mill operating without grinding elements, wherein mechanical activation of at least one of the reaction partners is effected by collision processes within a reaction chamber formed in a region of the fluid stream, and a solid body reaction to form the metal chelate is triggered. The novel method operates very energy-efficiently and with a high specific yield. It leads to a product having compact particles in the small, single-digit micrometer range having a comparatively narrow particle size distribution and a large surface. The product is homogenous and very pure. Thermal loading or decomposition of the organic chelate ligands, in particular of the amino acids, is likewise avoided, as are contaminants from milling and grinding element abrasion.
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Paragraph 0086-0087
(2021/10/11)
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- Synthesis method of p-methylsulfonylphenylserine copper
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The invention discloses a synthesis method of p-methylsulfonylphenylserine copper. One or more of copper hydroxide, basic cupric carbonate and copper oxide is or are used as a copper-bearing agent tosynthesize DL-p-methylsulfonylphenylserine copper, the reaction time is shortened, a mother liquor is used indiscriminately for multiple times, and the quantity of copper-bearing wastewater is reduced. The synthesis method comprises the following steps: adding the copper-bearing agent into a reaction flask, adding glycine, para-aldehyde and deionized water or adding the mother liquid in the last batch, reacting for 20 hours at the temperature of 40-55 DEG C, and cooling, filtering, washing and drying after finishing the reaction to obtain a product. The yield is 90% or higher, and the qualitymeets requirements. The method shortens the reaction time, and the copper-bearing mother liquid is used indiscriminately for multiple times.
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Paragraph 0024-0041;
(2019/05/08)
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- METAL COMPLEXES
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The disclosure provides metal complexes which have improved stability in the presence of humidity. The disclosure also provides a method of making metal complexes and uses thereof.
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Paragraph 0056;
(2018/06/29)
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- Potent inhibition of protein tyrosine phosphatase 1B by copper complexes: Implications for copper toxicity in biological systems
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A new dinuclear copper complex and several Cu-amino acid complexes inhibit protein tyrosine phosphatase 1B competitively at submicromolar levels, suggesting that copper complexes may interfere with cellular signaling pathways by inhibiting protein tyrosine phosphatases.
- Wang, Qingming,Lu, Liping,Yuan, Caixia,Pei, Kai,Liu, Zhiwei,Guo, Maolin,Zhu, Miaoli
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p. 3547 - 3549
(2010/07/16)
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- Hypoallergenic metal amino acid chelates and metal amino acid chelate-containing compositions
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Hypoallergenic metal amino acid chelate compositions, hypoallergenic formulations containing hypoallergenic metal amino acid chelates, methods of preparing hypoallergenic metal amino acid chelate, and methods of administering hypoallergenic metal amino acid chelates are provided. Specifically, the present invention provides metal amino acid chelates that are substantially free of allergens such that administration of the metal amino acid chelates to a subject in an effective amount to cause a medicinal or nutritional result does not produce a discernable adverse allergic reaction. The metal amino acid chelates can include chelates having a naturally occurring amino acid to metal molar ratio of from about 1:1 to 4:1.
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Page/Page column 6
(2008/06/13)
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- The enthalpy of interaction of copper(II) ions with KB-4 and ANKB-35 ionites and their low-molecular-weight analogues
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The enthalpies of interaction between copper(II) ions and KB-4 carboxyl cationite, ANKB-35 aminoacetic ampholyte, and their low-molecular-weight analogues (acetic and aminoacetic acids) and their dependences on the concentration of copper(II) ions and ligand groups in the system were determined microcalorimetrically.
- Kopylova,Amelin,Peregudov,Astapov
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p. 720 - 723
(2007/10/03)
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- 4-(2,4-diaminophenoxymethyl)-1,3-dioxolane secondary intermediates, processes for their production, and hair colorants
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Compounds of the formula (I): STR1 wherein R1, R2, R3 and R4 independently of one another may represent a hydrogen atom, a (C1-4) alkyl group, a hydroxy (C2-3) alkyl group, an alkoxy (C2-3) alkyl group, an amino (C2-3) alkyl group or a 2,3-dihydroxypropyl group and R5 and R6 independently of one another may represent hydrogen or a (C1-4) alkyl group, are made by reacting 2,4-dinitrohalobenzenes with 4-hydroxymethyl-1,3-dioxolanes under alkaline conditions to form 4-(2,4-dinitrophenoxymethyl)-1,3-dioxolanes, which are further reduced to the compounds of formula (I). In an alternate process, the 4-hydroxymethyl-1,3-dioxolanes are reacted with 4-halo-3-nitranilines or 2-halo-5-nitranilines, the product further reacted first under basic conditions with chloroformic acid ester followed by treatment with strong base, alkylation or alkoxylation, reduction, and optionally further alkylation of alkoxylation to arrive at the compounds (I). The compounds are useful as secondary intermediates in oxidative dyeing of keratinous fibers, particularly hair, and can be incorporated into compositions of various forms suitable for dyeing such fibers.
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- Substituted diaminophenols, and hair dyes containing such compounds
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Compounds of the formula (I) and their salts with inorganic and organic acids, STR1 in which R1 is a hydrogen atom or a trimethylsilyl group, R2, R3, R4, and R5 are, independently of each other, a hydrogen atom, a (C1 -C4) alkyl group, a hydroxy-(C2 -C3) alkyl group, an alkoxy-(C2 -C3) group, an amino-(C2 -C3) group, or a 2,3-dihydroxypropyl group, and in which R1, R2, R3, R4 and R5 are not simultaneously hydrogen atoms, and processes for their preparation and use as hair-coloring agents.
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- TERNARY MIXED-LIGAND COPPER(II) COMPLEXES WITH CHIRAL AMINOPHOSPHONIC ACIDS AND AMINO ACIDS
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Ternary mixed-ligand complexes of divalent copper, where one ligand is an α-aminoalkylphosphonic acid (APA) and the second ligand is L-phenylalanine, L-tyrosine, or L-hydroxyphenylalanine, are studied by potentiometric titration in aqueous at 25 deg C and μ=0.1.A maximum in the formation of the ternary complexes is exhibited at pH 7-8.The log Kst for the complexes formed and the statistical parameters characterizing the ternary complexes Δlog K and log X are determined.The effect of substituents on the α-carbon atom of the α-APA and of hydroxy groups on the phenyl substituent of the α-amino acids on the nature of the distribution of the complexes formed is studied.
- Nabirkina, E. P.,Ignat'eva, T. I.,Raevskii, O. A.,Belov, Yu. P.
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p. 2278 - 2281
(2007/10/02)
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- Syntheses and Characterisation of Complexes of Copper (II) Glycinates
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Copper(II) glycinate complexes with chloro, bromo and oxyanions like sulphate, perchlorate and nitrate as anionic ligands and potassium as cation, have been synthesised.The complexes are characterised by thermogravimetric analysis, magnetic suspectibility, electronic, infrared and EPR spectra measurement.The effect of introduction of these anions into the coordination polyhedra of Cu(II) and the nature of bonding in the resultant complexes have been discussed.
- Veeraiyan, V.,Udupa, M. R.
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p. 924 - 928
(2007/10/02)
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