Homophenylalanine-derived benzo[1,4]diazepine-2,5-diones are strong bacterial quorum sensing inhibitors.

Benzo[1,4]diazepines show a large diversity of biological activities and are still commonly used as medications against a broad range of diseases. Within our research in the field of chemo-enzymatic alkaloid synthesis, we developed a synthetic route towards close structural relatives, namely benzo[1,4]diazepine-2,5-diones. Possible antimicrobial activities of these substances are barely known up to date.

Synergy of experimental and computational chemistry: structure and biological activity of Zn(II) hydrazone complexes.

In this paper, three different Zn(II) complexes with ()-2-(2-(1-(6-bromopyridin-2-yl)ethylidene)hydrazinyl)-,,-trimethyl-2-oxoethan-1-aminium chloride (HLCl) have been synthesized and characterized by single crystal X-ray diffraction, elemental analysis, IR and NMR spectroscopy. All complexes are mononuclear, with the ligand (L) coordinated in a deprotonated formally neutral zwitterionic form NNO donor set atoms. Complex 1 forms an octahedral geometry with the composition [ZnL](BF), while complexes 2 [ZnL(NCO)] and 3 [ZnL(N)] form penta-coordinated geometry.

Cu(II) complexes with a salicylaldehyde derivative and α-diimines as co-ligands: synthesis, characterization, biological activity. Experimental and theoretical approach.

Copper(II) complexes with an α-diimine show a wide variety of biological activities, such as antibacterial, antifungal, antioxidant and anticancer. In this work, we synthesized and structurally characterized two novel Cu(II) complexes with methyl 3-formyl-4-hydroxybenzoate (HL) and α-diimines: 2,2'-bipyridine (bipy) and 1,10-phenanthroline (phen). Crystal structure analysis shows that the formulas of the compounds are [Cu(bipy)(L)(BF)] (1) and [Cu(phen)(L)(HO)](BF)·HO (2), with BF as a ligand in complex 1, which is rarely coordinated to metals.

Phycocyanobilin is a new binding partner of human alpha-2-macroglobulin that protects the protein against oxidative stress.

Under simulated physiological conditions, this study investigates the interaction between nutraceutical phycocyanobilin (PCB) and the universal anti-protease protein human alpha-2-macroglobulin (αM). Extensive molecular docking analyses on multiple α2M conformations, spectroscopic techniques, and α2M activity assays were utilized to examine the complex formation. The results revealed that for every protein conformation, two high energy binding sites exist: the first, conformationally independent, at the interface region between two monomer chains and the second, conformationally dependent, in the pocket composed of amino acids from four distinct domains (TED, RBD, CUB, and MG2) of the single protein chain.

The effects of biliverdin on pressure-induced unfolding of apomyoglobin: The specific role of Zn ions.

Apomyoglobin (apoMb), a model protein in biochemistry, exhibits a strong propensity to bind various ligands, which makes it a good candidate as a carrier of bioactive hydrophobic drugs. The stability of its hydrophobic pocket determines its potential as a carrier of bioactive compounds. High pressure (HP) is a potent tool for studying protein stability, revealing the specific role of hydrophobic cavities in unfolding.

Copper(II) complexes with 4-(diethylamino)salicylaldehyde and α-diimines: Anticancer, antioxidant, antigenotoxic effects and interaction with DNA and albumins.

In this article, cytotoxicity, the mechanisms of cytotoxic activity, genotoxicity, and interaction with DNA and proteins, of two Cu(II) complexes with a salicylaldehyde derivative (4-(diethylamino)salicylaldehyde) and α-diimine (2,2'-bipyridine (bipy) and 1,10-phenanthroline (phen)) are reported. Both Cu(II) complexes performed cytotoxic effects against all tested malignant cell lines. Complexes exerted highest cytotoxicity against HeLa and A375 malignant cell lines.

Selective formation of dihydrofuran fused [60] fullerene derivatives by TEMPO mediated [3 + 2] cycloaddition of medium chain β-keto esters to C.

In this study, β-keto esters as readily available bio-based building blocks were used to decorate the C sphere. Generally, cyclopropanated fullerene derivatives are obtained by the standard Bingel-Hirsch procedure. Herein, omitting the iodine from the reaction mixture and adding TEMPO afforded dihydrofuran fused C fullerene derivatives.

Antipsychotic clozapine binding to alpha-2-macroglobulin protects interacting partners against oxidation and preserves the anti-proteinase activity of the protein.

In this study, the interaction between clozapine, an atypical antipsychotic drug, and alpha-2-macroglobulin (αM), a multipurpose anti-proteinase, was investigated under simulated (patho) physiological conditions using multiple spectroscopic techniques and molecular modeling. It was found that αM binds clozapine with a moderate affinity (the binding constant of 0.9 × 10 M at 37 °C).

Assessing the potential of para-donor and para-acceptor substituted 5-benzylidenebarbituric acid derivatives as push-pull electronic systems: Experimental and quantum chemical study.

Electronic interactions in donor-π-linker-acceptor systems with barbituric acid as an electron acceptor and possible electron donor were investigated to screen promising candidates with a push-pull character based on experimental and quantum chemical studies. The tautomeric properties of 5-benzylidenebarbituric acid derivatives were studied with NMR spectra, spectrophotometric determination of the pKa values, and quantum chemical calculations. Linear solvation energy relationships (LSER) and linear free energy relationships (LFER) were applied to the spectral data - UV frequencies and C NMR chemical shifts.

Theoretical modeling of sorption of metal ions on amino-functionalized macroporous copolymer in aqueous solution.

With regard to the harmful effects of heavy metals on human health and the environment, the demand for synthesis and investigation of macromolecules with large capacity of harmful substances sorption is ever greater. Quantum-chemical methods may be applied in structural modeling, prediction, and characterization of such molecules and reactions. Sorption of metal ions (Cu, Cd, Co, and Ni) to triethylenetetramine-functionalized copolymer poly(GMA-co-EGDMA)-teta was successfully modeled by quantum chemical calculations, at the B3LYP//6-311++G**/lanl2dz level.

Stabilization of apo α-lactalbumin by binding of epigallocatechin-3-gallate: Experimental and molecular dynamics study.

α-Lactalbumin (ALA) is a Ca-binding protein which constitutes up to 20% of whey protein. At acidic pH, and in the apo-state at elevated temperatures, ALA is the classic 'molten globule' (MG). This study examined epigallocatechin-3-gallate (EGCG) binding to ALA in its apo form (apoALA) and stabilizing effect on protein structure thereof.

Covalent binding of food-derived blue pigment phycocyanobilin to bovine β-lactoglobulin under physiological conditions.

In this study, we investigated structural aspects of covalent binding of food derived blue pigment phycocyanobilin (PCB) to bovine β-lactoglobulin (BLG), major whey protein, by spectroscopic, electrophoretic, mass spectrometry and computational methods. At physiological pH (7.2), we found that covalent pigment binding via free cysteine residue is slow (k = 0.

Positive and negative nano-electrospray mass spectrometry of ruthenated serum albumin supported by docking studies: an integrated approach towards defining metallodrug binding sites on proteins.

Binding of three ruthenium(ii) compounds of general formula mer-[Ru(L3)(N-N)X][Y] (where L3 = 4'-chloro-2,2':6',2''-terpyridine (Cl-tpy); N-N = 1,2-diaminoethane (en), 1,2-diaminocyclohexane (dach) or 2,2'-bipyridine (bipy); X = Cl; Y = Cl) to human serum albumin (HSA) has been investigated by nano-LC/nano-ESI MS and docking studies. A bottom-up proteomics approach has been applied for the structural characterization of metallated proteins and the data were analyzed in both the positive and negative ion mode. The negative ion mode was achieved after the post-column addition of an isopropanol solution of formaldehyde that enabled sample ionization at micro-flow rates.

Detailed solvent, structural, quantum chemical study and antimicrobial activity of isatin Schiff base.

The ratios of E/Z isomers of sixteen synthesized 1,3-dihydro-3-(substituted phenylimino)-2H-indol-2-one were studied using experimental and theoretical methodology. Linear solvation energy relationships (LSER) rationalized solvent influence of the solvent-solute interactions on the UV-Vis absorption maxima shifts (ν) of both geometrical isomers using the Kamlet-Taft equation. Linear free energy relationships (LFER) in the form of single substituent parameter equation (SSP) was used to analyze substituent effect on pK, NMR chemical shifts and ν values.

Characterization and effects of binding of food-derived bioactive phycocyanobilin to bovine serum albumin.

Phycocyanobilin (PCB) is a blue tetrapyrrole chromophore of C-phycocyanin, the main protein of the microalga Spirulina, with numerous proven health-related benefits. We examined binding of PCB to bovine serum albumin (BSA) and how it affects protein and ligand stability. Protein fluorescence quenching and microscale thermophoresis demonstrated high-affinity binding (K=2×10M).

in/out Isomerism of cyclophanes: a theoretical account of 2,6,15-trithia-[3][7]metacyclophane and [3][7]metacyclophane as well as their halogen substituted analogues.

A detailed theoretical investigation of cyclophanes with a divergent set of methods ranging from molecular mechanics through semiempirical to ab initio is presented. Cyclophanes have attracted interest over the years due to their unusual chemistry and increasing applications. There has been previous debate over the effects contributing to the greater stability of more-crowded in isomers of certain cyclophanes, and a higher strain in the out isomer was the prevailing explanation.

Stabilization of Human Serum Albumin by the Binding of Phycocyanobilin, a Bioactive Chromophore of Blue-Green Alga Spirulina: Molecular Dynamics and Experimental Study.

Phycocyanobilin (PCB) binds with high affinity (2.2 x 106 M-1 at 25°C) to human serum albumin (HSA) at sites located in IB and IIA subdomains. The aim of this study was to examine effects of PCB binding on protein conformation and stability.

Solvent and structural effects in tautomeric 2(6)-hydroxy-4-methyl-6(2)-oxo-1-(substituted phenyl)-1,2(1,6)-dihydropyridine-3-carbonitriles: UV, NMR and quantum chemical study.

The state of the tautomeric equilibria of 2(6)-hydroxy-4-methyl-6(2)-oxo-1-(substituted phenyl)-1,2(1,6)-dihydropyridine-3-carbonitriles, 2-PY/6-PY, was evaluated using experimental and theoretical methodology. The experimental data were interpreted with the aid of time-dependent density functional (TD-DFT) method. Electron charge density was obtained by the use of Quantum Theory of Atoms in Molecules, i.

Complexes of green tea polyphenol, epigalocatechin-3-gallate, and 2S albumins of peanut.

2S albumins of peanuts are seed storage proteins, highly homologous in structure and described as major elicitors of anaphylactic reactions to peanut (allergens Ara h 2 and Ara h 6). Epigallocatechin-3-gallate (EGCG) is the most biologically potent polyphenol of green tea. Non-covalent interactions of EGCG with proteins contribute to its diverse biological activities.

Contribution of anion-π interactions to the stability of Sm/LSm proteins.

We have analyzed the influence of anion-π interactions to the stability of Sm/LSm assemblies. The side chain of Glu is more likely to be in anion-π interactions than Asp. Phe has the highest occurrence in these interactions than the other two π residues.

Nature of the water/aromatic parallel alignment interactions.

The water/aromatic parallel alignment interactions are interactions where the water molecule or one of its O-H bonds is parallel to the aromatic ring plane. The calculated energies of the interactions are significant, up to ΔE(CCSD)(T)(limit) = -2.45 kcal mol(-1) at large horizontal displacement, out of benzene ring and CH bond region.

Interactions of epigallo-catechin 3-gallate and ovalbumin, the major allergen of egg white.

Polyphenols, the potent plant secondary metabolites, have beneficial effects on human health, but the mechanism(s) by which these effects are exerted is not well understood. Here, we present the detailed analysis of the interactions between the major green tea catechin, epigallo-catechin 3-gallate (EGCG), and the major dietary protein and allergen, ovalbumin (OVA). We show that EGCG binds to the pocket that partly overlaps with the previously identified IgE-binding region in OVA, and that this interaction induces structural changes in the allergen.

A comparative study of in vitro cytotoxic, antioxidant, and antimicrobial activity of Pt(II), Zn(II), Cu(II), and Co(III) complexes with N-heteroaromatic Schiff base (E)-2-[N'-(1-pyridin-2-yl-ethylidene)hydrazino]acetate.

In search for novel biologically active metal based compounds, an evaluation of in vitro cytotoxic, antioxidant, and antimicrobial activity of new Pt(II) complex and its Zn(II), Cu(II), and Co(III) analogues, with NNO tridentately coordinated N-heteroaromatic Schiff base ligand (E)-2-[N'-(1-pyridin-2-yl-ethylidene)hydrazino]acetate, was performed. Investigation of antioxidative properties showed that all of the compounds have strong radical scavenging potencies. The Zn(II) complex showed potent inhibition of DNA cleavage by hydroxyl radical.

Solvent and structural effects on the UV absorption spectra of N-(substituted phenyl)-2-cyanoacetamides.

UV absorption spectra of N-(substituted phenyl)-2-cyanoacetamides have been recorded in the range 200-400 nm in the set of selected solvents. The solute-solvent interactions were analyzed on the basis of linear solvation energy relationships (LSER) concept proposed by Kamlet and Taft. The effects of substituents on the absorption spectra were interpreted by correlation of absorption frequencies with Hammett substituent constant, σ.