Bis(amino acidato)copper(II) compounds in blood plasma: a review of computed structural properties and amino acid affinities for Cu informing further pharmacological research.

Neutral bis(amino acidato)copper(II) [Cu(aa)] coordination compounds are the physiological species of copper(II) amino acid compounds in blood plasma taking the form of bis(l-histidinato)copper(II) and mixed ternary copper(II)-l-histidine complexes, preferably with l-glutamine, l-threonine, l-asparagine, and l-cysteine. These amino acids have three functional groups that can bind metal ions: the common α-amino and carboxylate groups and a side-chain polar group. In Cu(aa), two coordinating groups per amino acid bind to copper(II) in-plane, while the third group can bind apically, which yields many possibilities for axial and planar bonds, that is, for bidentate and tridentate binding.

Structure prediction of physiological bis(amino acidato)copper(II) species in aqueous solution: The copper(II) compounds with l-glutamine and l-histidine.

Neutral (l-histidinato)(l-glutaminato)copper(II) [Cu(His)(Gln)] has been established as the most abundant ternary copper(II) amino acid compound of the exchangeable copper(II) pool in blood plasma. The experimental studies of Cu(His)(Gln) and bis(glutaminato)copper(II) [Cu(Gln)] in solutions did not specify their complete geometries. To determine the geometries, this paper investigates the conformers, energy landscapes, and a structure-magnetic parameters relation of Cu(Gln) and Cu(His)(Gln) by the density functional theory (DFT) calculations.

Structure prediction of neutral physiological copper(II) compounds with l-cysteine and l-histidine.

Bis(aminoacidato)copper(II) [Cu(aa)] coordination compounds are the physiological species of copper(II) amino acid compounds in blood plasma. Since there are no experimental data in the literature about the geometries that physiological Cu(aa) could form with l-cysteine (Cys), that is, for bis(l-cysteinato)copper(II) [Cu(Cys)] and the ternary (l-histidinato)(l-cysteinato)copper(II) [Cu(His)(Cys)], this paper computationally examines the possible conformations that the two compounds could form with the Cys ligand having a protonated sulfur, as in the conventional zwitterion, which was determined to be prevailing in aqueous solution. These two amino acids can bind metals in a tridentate fashion and thus form many possible coordination patterns.

Conformational Analyses of Physiological Binary and Ternary Copper(II) Complexes with l-Asparagine and l-Histidine; Study of Tridentate Binding of Copper(II) in Aqueous Solution.

This study explores the structural properties and energy landscapes of the physiologically important bis(l-asparaginato)copper(II) [Cu(l-Asn)] and (l-histidinato)(l-asparaginato)copper(II) [Cu(l-His)(l-Asn)]. The conformational analyses in the gas phase and implicitly modeled water medium, and magnetic parameters of electron paramagnetic resonance spectra were attained using density functional theory calculations. The apical Cu coordination and hydrogen bonding were analyzed.

Calculating the geometry and Raman spectrum of physiological bis(L-histidinato)copper(II): an assessment of DFT functionals for aqueous and isolated systems.

Reliable density functional theory (DFT) calculations can be performed in conjuction with spectroscopic measurements to elucidate the structural properties of physiologically important bis(amino acidato)copper(II) compounds in solutions. They can provide insight into the influence of intermolecular interactions on the molecular geometry in the crystal lattice or solution when compared with a DFT gas-phase minimum. Our previous paper [Marković et al.

The Important Role of the Hydroxyl Group on the Conformational Adaptability in Bis(l-threoninato)copper(II) Compared to Bis(l-allo-threoninato)copper(II): Quantum Chemical Study.

Detailed structural properties of physiological bis(amino acidato)copper(II) complexes are generally unknown in solutions. This paper examines how stereochemical differences between the essential amino acid l-threonine and its diastereomer l-allo-threonine, which is rarely present in nature, may affect relative stabilities of bis(l-threoninato)copper(II) and bis(l-allo-threoninato)copper(II) in the gas phase and aqueous solution. These amino acids can bind to Cu(II) via the nitrogen and carboxylato oxygen atoms, the nitrogen and hydroxyl oxygen atoms, and the carboxylato and hydroxyl oxygen atoms.

Solid-State NMR Study of Paramagnetic Bis(alaninato-κ(2)N,O)copper(II) and Bis(1-amino(cyclo)alkane-1-carboxylato-κ(2)N,O)copper(II) Complexes: Reflection of Stereoisomerism and Molecular Mobility in (13)C and (2)H Fast Magic Angle Spinning Spectra.

Solid-state stereochemistry and mobility of paramagnetic copper(II) complexes formed by aliphatic amino acids (l-alanine, d,l-alanine, 1-amino-2-methyl-alanine) and 1-amino(cyclo)alkane-1-carboxylic acids (alkane = propane, butane, pentane, hexane) as bidentate ligands has been studied by (13)C and (2)H solid-state fast magic angle spinning (MAS) NMR spectroscopy. We examined the prospective method to characterize solid-state paramagnetic compounds in a routine way. Both (13)C and (2)H MAS spectra can distinguish d,l and l,l diastereomers of natural and polydeuterated bis([Dn]alaninato)copper(II) (n = 0, 2, 8) complexes with axial and/or equatorial methyl positions (conformations) primarily due to different Fermi-contact (FC) contributions.

Combined experimental and computational study of cis-trans isomerism in bis(L-valinato)copper(II).

Heating of polycrystalline cis aquabis(L-valinato)copper(II) at 90 °C resulted in a dehydrated powder. Recrystallization from aqueous solution of the obtained product yielded anhydrous trans bis(L-valinato)copper(II). The X-ray crystal and molecular structures of trans bis(L-valinato)copper(II) and cis aquabis(L-valinato)copper(II) are presented.

Structure Prediction of Bis(amino acidato)copper(II) Complexes with a New Force Field for Molecular Modeling.

This article presents a new force field whose parameterization was based on experimental crystal data and quantum chemically obtained vacuum structures of a series of copper(II) complexes with aliphatic α-amino acids and their N-alkyl derivatives, along with the SPC/E water model. The ability of the new force field to reproduce and predict the structural properties of the copper(II) complexes in the gas phase, in simulated crystalline surroundings, and solvated in water is examined. Molecular dynamics (MD) simulations with the new force field yielded time-average structural coordinates of bis(glycinato)copper(II) [the only one of 25 modeled bis(amino acidato)copper(II) systems with published experimental structural data in aqueous solution at room temperature] within the experimental error values.

Is the enthalpy of fusion of tris(acetylacetonato)metal(III) complexes affected by their potential energy in the crystal state?

In this Article we present enthalpies of fusion and melting points obtained from new thermochemical measurements of tris(acetylacetonato)metal(III), M(acac)(3), complexes (M = Fe, Al, Cr, Mn, Co) using differential scanning calorimetry (DSC) and evaluate them in relation to their different values found in the literature. An enthalpy of fusion of 27.67 kJ mol(-)(1) was derived for Mn(acac)(3) from a symmetrical DSC thermogram captured for the first time.

Modeling anhydrous and aqua copper(II) amino acid complexes: a new molecular mechanics force field parametrization based on quantum chemical studies and experimental crystal data.

This paper presents the vacuum structures of aquacopper(II) bis(amino acid) complexes with glycine, sarcosine, N,N-dimethylglycine, and N-tert-butyl-N-methylglycine estimated using the B3LYP method. The differences between the B3LYP vacuum structures and experimental crystal structures suggested considerable influence of crystal lattice packing effects on the changes in the complexes' geometries. A previously developed molecular mechanics force field for modeling anhydrous copper(II) amino acidates was reoptimized to simulate these changes and predict the properties of both trans and cis anhydrous and aqua copper(II) amino acid complexes.

The influence of amino acid side chains on water binding to the copper(II) in bis(N,N-dimethyl-L-alpha-isoleucinato)-copper(II): an EPR and molecular mechanics study.

Simulations were done of the electron paramagnetic resonance (EPR) spectra for bis(N,N-dimethyl-L-alpha-isoleucinato)copper(II) dissolved in deuterated methanol as a function of temperature. They indicated different behaviour of the complex below and above 300 degrees K. The effect was examined by the conformational analysis of the copper(II) complex with a new molecular mechanics force field.

Why Are Copper(II) Amino Acid Complexes Not Planar in Their Crystal Structures? An ab Initio and Molecular Mechanics Study.

This paper presents geometries of copper(II) chelates with L-alanine, L-leucine, and L-N,N-dimethylvaline optimized by the hybrid density functional method B3LYP. According to the molecular quantum mechanics results, a square-planar copper(II) coordination geometry is electronically favored in vacuo. Deviations from the planar configuration observed in the crystal state should be attributed to sterical intramolecular and/or intermolecular effects.