Histidine Complexes Research Articles

A DFT study of isolated histidine interactions with metal ions (Ni2+, Cu2+, Zn2+) in a six-coordinated octahedral complex.

Understanding the role that metal ions play in biological and material processes is critical to addressing a number of diseases and problems facing society today. There have been a number of studies that have begun to approach this concern from a myriad of different perspectives. However, there is still a considerable lack of understanding concerning the mechanisms and structures of metal-related problems, specifically biological and medical-related issues. Understanding the mechanism of ingestion and uptake of metals into the human body is critical to addressing many diseases such as Alzheimer's and certain types of cancers. Using computational techniques, this work adds to the overall understanding of metal interactions with proteins by focusing on metal ion interactions with the amino acid, histidine, one of the most common sites of metal attachment. In this work, the geometries of single and dual histidines attached to Ni2+, Cu2+, and Zn2+ ions at B3LYP/6-311G(d) are presented. The results show stable octahedral complexes associated with each of the metal ions. Free energy calculations suggest that all three complexes are spontaneous in the formation of the dual histidine-metal complexes. Nickel and copper are spontaneous in the formation of the single histidine complex, although the copper complex undergoes slight geometric changes. Zinc is found to be nonspontaneous in forming the single histidine complex. Finally, the reduction potential of the single histidine-metal complex is presented. All of the complexes show positive reduction potentials. However, the nickel and copper complexes undergo geometrical changes to adopt a square planar conformation. Graphical abstract The impact of metal ions in biological systems is of great importance to understanding a diverse number of diseases. By understanding the fundamentals of select ions complexed with histidines, greater understanding of the mechanisms of actions these ions play in health may be elucidated. This work presents initial structures and thermodynamics of histidine complexes with nickel, copper, and zinc metal ions.

A chemical speciation insight into the palladium(ii) uptake and metabolism by Sinapis alba. Exposure to Pd induces the synthesis of a Pd-histidine complex.

Palladium is recognized as a technologically critical element (TCE) because of its massive use in automobile exhaust gas catalytic converters. The release of Pd into the environment in the form of nanoparticles of various size and chemical composition requires an understanding of their metabolism by leaving organisms. We provide here for the first time a chemical speciation insight into the identity of the ligands produced or used by a plant Sinapis alba L. exposed in hydropony to Pd nanoparticles and soluble Pd (nitrate). The analytical method developed was based on the concept of 2D HPLC with parallel inductively coupled plasma mass spectrometry (ICP MS) and electrospray MS detection. Size exclusion chromatography - ICP MS of the plant extracts showed no difference between the speciation of Pd after the exposure to nanoparticles and after that to Pd2+ which indicated the reactivity and dissolution of Pd nanoparticles. A comparative investigation of the Pd speciation in a control plant extract spiked with Pd2+ and of an extract of a plant having metabolized palladium indicated the response of the Sinapis alba by the formation of a Pd-histidine complex. The complex was identified via Orbitrap MS; the HPLC-MS chromatogram produced two peaks at m/z 415.0341 each corresponding to a Pd-His2 complex. An investigation by ion-mobility MS revealed a difference in their collision cross section indicating that the complexes present varied in terms of spatial conformation. A number of other Pd complexes with different ligands (including nicotianamine) circulating in the plant were detected but these ligands were already observed in a control plant and their concentrations were not affected by the exposure to Pd.

Synthesis, Characterization and Antimicrobial Activity of Cu (II), Co (II) and Ni (II) Histidine Complexes

Ternary complexes of histidine amino acid (Schiff base) were synthesized, characterized and tested against multi-drug resistant pathogens. The metal ion centers included Cu (II), Ni (II) and Co (II). These complexes were characterized using physico-chemical and spectroscopic analytical methods. All the complexes are found to be considerably soluble in both polar and non-polar solvents including methanol, ethanol, butanol, acetone, ethyl acetate, and benzene and di ethyl-ether. Electronic Absorption Studies using FT-IR spectrophotometer revealed ν (O-H), ν (C=O), ν (C=N), ν (M -N) and ν (M-O) occurred between 3410 - 3417, 1751 - 1753, 1519 – 1521, 671 – 678, 439 – 470 cm- 1 respectively in complexes and ligand. UV-Visible was further used to elucidate the complexes resulting in transitions characteristics of the ligand and complexes. The Schiff base showed no antimicrobial activity at various therapeutic concentrations. However, the metal complexes exhibited broad spectrum antibiotic activities against the multi-drug resistant pathogens at minimum inhibitory concentration (MIC ≤ 200 µg/ml). The metal complexes showed strong activity against the isolates at medium and high concentrations, the bacteria strains included E.coli , P. aeruginosa, S. typhi and S. aureus and the fungi strains of Candida albicans , Aspergillus flavus and Aspergillus niger . The bioactivity recorded against these multi drug resistant pathogens indicates the potentials of these complexes for further therapeutic studies. Keywords : Histidine complex, synthesis, characterisation, antimicrobial activity, pathogens.

Influence of Cationic Cetyltrimethylammonium Bromide on Rate of Zn(II)-Histidine Complex and Ninhydrin.

Paper analyses the influence of cationic cetyltrimethylammonium bromide on rate of Zn(II)-histidine and ninhydrin. UV-visible spectroscopy was applied to note absorbance of Zn(II)-histidine complex with ninhydrin at the end of reaction in the two systems. Rate constant, kobs, (in aqueous) and rate constant, kψ, (in cetyltrimethylammonium bromide, CTAB) were determined by computer software. Reactions depict first-order in Zn(II)-histidine concentration and fractional-order in ninhydrin concentration in aqueous and micellar media. The results achieved indicate that the reactions take place principally by the same reaction mechanism in both the media. Critical micelle concentration of CTAB surfactant was calculated by recording the conductivity as a function of surfactant concentrations. Influence of various amounts of surfactant on Zn(II)-histidine complex and ninhydrin reaction was performed under different reaction conditions. Reaction was catalyzed and accelerated efficiently by surfactant medium compared to aqueous medium. The observed influence of surfactant on rate has been mentioned in details and their quantitative treatment of kinetic results have been deduced by the means of Menger and Portnoy model for micellar catalysis.

Effect of supplementing chromium histidinate and picolinate complexes along with biotin on insulin sensitivity and related metabolic indices in rats fed a high-fat diet.

ScopeTo investigate the effects of chromium histidinate (CrHis) and chromium picolinate (CrPic) complex along with biotin to a high‐fat diet (HFD) fed to rats on the insulin sensitivity and the anti‐obesity properties.MethodsForty‐two Sprague–Dawley male rats were divided into six groups. The rats were fed either (a): a standard diet (Control) or (b): a HFD or (c): a HFD with biotin (HFD+B) or (d): a combination of HFD and biotin along with CrPic (HFD + B + CrPic) or (e): a combination of HFD and biotin along with CrHis (HFD + B + CrHis) or (f): a combination of HFD and biotin along with CrHis and CrPic (HFD + B + CrHis + CrPic).ResultsAdding biotin with chromium to HFD improved the glucose, insulin, HOMA‐IR, leptin, lipid profile, with HFD+B+CrHis treatment being the most effective (p = 0.0001). Serum, liver, and brain tissue Cr concentrations increased upon Cr supplementations (p = 0.0001). Supplementing CrHis along with biotin to a HFD (HFD + B + CrHis) provided the greatest levels of GLUT‐1, GLUT‐3, PPAR‐γ, and IRS‐1, but the lowest level of NF‐κB in the brain and liver tissues.ConclusionBiotin supplementation with chromium complexes, CrHis in particular, to a HFD pose to be a potential therapeutic feature for the treatment of insulin resistance.

Periodic changes in the oxidation states of the center ion in the cobalt-histidine complex induced by the BrO3- - SO32- pH-oscillator.

The coupling of acid-base type pH-dependent equilibria to pH-oscillators expanded significantly the number and type of species which can participate in oscillatory chemical processes. Here, we report a new version of oscillatory phenomena that can appear in coupled oscillators. Oscillations in the oxidation states of the center ion bound in a chelate complex were generated in a combined system, when the participants of the oscillator as dynamical unit and the components of the complex formation interacted with each other through redox reaction. It was demonstrated, when the BrO3- - SO32- pH-oscillator and the Co2+ - histidine complex were mixed in a continuous stirred tank reactor, periodic changes in the pH were accompanied with periodic transitions in the oxidation number of the cobalt ion between +2 and +3. The oscillatory build up and removal of the Co(III)-complex were followed by recording the light absorption at the wavelength characteristic for this species with simultaneous monitoring the pH-oscillations. The dual role of the SO32- ion in the explanation of this observation was pointed out. Its partial and consecutive total oxidations by BrO3- give rise to and maintain sustained pH-oscillations in the combined system and its presence induces the rapid conversion of the Co2+ to a highly inert Co(III)-histidine chelate when the system jumps to and remains in the high pH-state. The oscillatory cycle is completed when the Co(III)-complex is washed out from the reactor and the reagents are replenished by the flow during the time the system spends in the acidic range of pH. The idea, to couple a core oscillator to an equilibrium through a redox reaction that takes place between the constituents of the oscillator and the target species of the linked subsystem, may be generally used to bring about forced oscillations in many other combined chemical systems.

Oxido‐peroxido W(VI)‐histidine–MgAl‐layered double hydroxide composite as an efficient catalyst in sulfide oxidation

Oxido‐peroxido W(VI)‐histidine–MgAl‐layered double hydroxide composite was prepared by using MgAl‐layered double hydroxide as a host and oxido‐peroxido W(VI)‐histidine complex as a guest. The composite was characterized by XRD, IR, EDX,SEM and TEM techniques. This composite is tested for catalytic selective sulfoxidation reactions using hydrogen peroxide as oxidant showing good to moderate conversion along with high selectivity.

Self-Assembled Binuclear Cu(II)-Histidine Complex for Absolute Configuration and Enantiomeric Excess Determination of Naproxen by Tandem Mass Spectrometry.

Naproxen is one of the most consumed nonsteroidal anti-inflammatory drugs and marketed as S-naproxen since R-naproxen is hepatotoxic. In this study, chiral recognition of naproxen has been investigated by tandem mass spectrometry (MS/MS). Among all diastereomeric complexes formed between naproxen and the examined chiral selectors, including cyclodextrins (α/β/γ-CD), modified phenylalanines ( N-acetyl-phenylalanine, N-t-butoxycarbonyl-phenylalanine, N-9-fluorenylmethyloxycarbonyl-phenylalanine), amino acids (Trp, Phe, Tyr, His), glucose, tartaric acid, and vancomycin, a novel binuclear metal bound diastereomeric complexes [(M(II))2( S/ R-naproxen)(l-His)2-3H]+ (M = Cu, Ni, or Co with Cu being the best) could allow effective identification of the absolute configuration of naproxen and determination of its enantiomeric excess ( ee) through MS/MS analysis. The key candidate structure of [(Cu(II))2( S/ R-naproxen)(l-His)2-3H]+ has been revealed by means of collision-induced dissociation, ion mobility mass spectrometry and density functional theory calculations, indicating an interesting and unusual self-assembled compact geometry with the two Cu(II) ions bridged closely together (Cu-Cu distance is 3.04 Å) by the carboxylate groups of the two histidines. It was shown that the difference in dissociation efficiency between the two diastereomers was attributed to the interaction between the NH2 bond of the amino group of one histidine and the naphthyl ring of naproxen. The present report is the first to observe and characterize the complex of (Cu(II))2(His)2 with aromatic acid, which could contribute to the chiral recognition of other chiral aromatic acids, design of catalysts based on binuclear copper bound complex, as well as the better understanding of metal ion complexation by His or His-containing ligands.

Determination of the Formation Constant of Some Transition Metal Ion- histidine Complexes in Water and Water-dioxane and Evaluation of their Thermodynamic Parameters

Determination of the Formation Constant of Some Transition Metal Ion- histidine Complexes in Water and Water-dioxane and Evaluation of their Thermodynamic Parameters

Kinetic investigation on the oxidation of N -acetyl cysteine by dioxygen of μ-dioxytetrakis(histidinato)dicobalt(II) complex

At neutral and alkaline pH cobalt(II)histidine complex binds with molecular oxygen reversibly to form μ-dioxytetrakis(histidinato)dicobalt(II), an oxygen adduct complex. The reaction proceeds in such a way that the addition of N-acetyl cysteine to μ-dioxytetrakis(histidinato)dicobalt(II) results in the fading away of brown color of μ-dioxytetrakis(histidinato)dicobalt(II) due to the oxidation of N-acetyl cysteine. Thus, kinetic measurement of this oxidation was exploited and studied spectrophotometrically at different concentration of N-acetyl cysteine, μ-dioxytetrakis(histidinato)dicobalt(II) and hydroxide ion. Effect of μ-dioxytetrakis(histidinato)dicobalt(II) was studied in the concentration range from 1.0 × 10− 3 mol dm− 3 to 5.0 × 10− 3 mol dm− 3 and it was found that rate constant was independent on [Co(II)histidine] with the average value of rate constant 1.11 × 10− 3 s− 1. It was observed that the values of rate constant were found to be independent of [N-acetyl cysteine] at higher concentrations, but, varied linearly with [N-acetyl cysteine] at lower concentrations (1–6 × 10− 3 mol dm− 3). The values of rate constant increased from 1.17 × 10− 3 s− 1 (at [NaOH] = 5.0 × 10− 4 mol dm− 3) to 2.55 × 10− 3 s− 1 when the concentration of NaOH is increased to 1.0 × 10− 2 mol dm− 3.

Tunable Aggregation-Induced Emission of Polyoxometalates via Amino Acid-Directed Self-Assembly and Their Application in Detecting Dopamine

In this work, through the aqueous phase self-assembly of an Eu-containing polyoxometalate (POM), Na9[EuW10O36]·32H2O (EuW10) and different amino acids, we obtained spontaneously formed vesicles that showed luminescence enhancement for EuW10 and arginine (Arg), lysine (Lys), or histidine (His) complexes, but luminescence quenching for EuW10 and glutamic acid (Glu) or aspartic acid (Asp) complexes. The binding mechanisms between them have been explored at the molecular level by using different characterization techniques. It was found that EuW10 acted as polar head groups interact with the positively charged residues for alkaline amino acids, protonated amide groups for acidic amino and nonpolar acid aminos through electrostatic interactions, and the remaining segments of amino acids served as relatively hydrophobic parts aggregated together forming bilayer membrane structures. Moreover, the different influences of amino acids on the fluorescence property of EuW10 revealed that the electrostatic interaction between the positive charged group of amino acid and the polyanionic cluster dominates the fluorescence properties of assemblies. Furthermore, a turn-off sensing application of the EuW10/Arg platform to probe dopamine (DA) against various other biological molecules such as neurotransmitters or amino acids was also established. The concept of combining POMs with amino acids extends the research category of POM-based functional materials and devices.

Immobilized Vanadium Histidine and Tryptophan Schiff Base Complexes on Modified Magnetite Nanoparticles as Epoxidation Catalyst

In this study, magnetically recoverable vanadium complexs designated as VO(Sal-Tryp)/AmpSCMNPs and VO(Sal-His)/AmpSCMNPs were prepared through immobilization of Schiff bases of histidine or tryptophan with salicylaldehyde on the surface of modified silica coated iron oxide magnetite nanoparticles with (3-aminopropyl) trimethoxysilane as aminopropyl (Amp) spacer followed by complexation with VOSO4. Characterization was carried out by chemical analysis, Fourier transform infrared spectroscopy, XRD, scanning electron microscopy and vibrating sample magnetometry techniques. VO(Sal-Tryp)/AmpSCMNPs and VO(Sal-His)/AmpSCMNP were found to catalyze the epoxidation of allyl alcohols and olefins with tert-butyl hydroperoxide with excellent conversions and selectivities. Investigation of the stability and reusability revealed the heterogeneity character of the catalyst with no desorption during the course of epoxidation reactions. High yields, clean reactions, easily catalyst separation and recyclability of the solid catalyst are some advantages of this method.

Properties of gold electrode modified with dimercaptosuccinic acid and electrochemical behavior of copper histidine complex

A self-assembled monolayer of meso-2,3-dimercaptosuccinic acid was prepared on the surface of gold disc electrode. The modified electrode was characterized using cyclic voltammetry in copper(II) solution and cyclic voltammetry and electrochemical impedance spectroscopy in the presence of potassium hexacyanoferrate( II)/(III) and hexaammineruthenium (II)/(III) chloride. Binding of copper(II) histidine complex (Cu–His) onto the electrode was successfully achieved for a wide range of tested concentrations, as shown with adsorption transfer stripping voltammetry. Electrode response (logΔIp) was linearly proportional to logc(Cu–His) with correlation coefficient R32 = 0.9839.

X-ray absorption near-edge structure study on the configuration of Cu2+/histidine complexes at different pH values**Project supported by the National Natural Science Foundation of China (Grant No. 11205186).

The local configurations around metal ions in metalloproteins are of great significance for understanding their biological functions. Cu2+/histidine (His) is a typical complex existing in many metalloproteins and plays an important role in lots of physiological functions. The three-dimensional (3D) structural configurations of Cu2+/His complexes at different pH values (2.5, 6.5, and 8.5) are quantitatively determined by x-ray absorption near-edge structure (XANES). Generally Cu2+/His complex keeps an octahedral configuration consisting of oxygen atoms from water molecules and oxygen or nitrogen atoms from histidine molecules coordinated around Cu2+. It is proved in this work that the oxygen atoms from water molecules, when increasing the pH value from acid to basic value, are gradually substituted by the Ocarboxyl, Nam, and Nim from hisitidine molecules. Furthermore, the symmetries of Cu2+/His complexes at pH 6.5 and pH 8.5 are found to be lower than at pH 2.5.

Investigation of the structural characterization and reversible oxygenation mechanism of oxygenated cobalt–3-(4-thiazolyl)-l-alanine and cobalt–histidine complexes using electrospray tandem mass spectrometry

A new ESI-MS method was developed to identify oxygenated species in Co–Tza formed by the uptake of dioxygen. The structures and fragmentation mechanisms of Co–Tza and Co–His were deduced.

Properties of Gold Electrode Modified with Dimercaptosuccinic Acid and Electrochemical Behavior of Copper Histidine Complex

Properties of Gold Electrode Modified with Dimercaptosuccinic Acid and Electrochemical Behavior of Copper Histidine Complex

Activation of molecular oxygen for the oxidation of 2-mercaptoethanol: A kinetic and mechanistic approach

Reduction of molecular oxygen by 2-mercaptoethanol in the presence of cobalt(II)histidine is described. Cobalt(II)histidine complex forms dinuclear 2:1 (Co:O2) complex with molecular oxygen (μ-dioxytetrakis(histidinato)dicobalt(II)). The molecular oxygen did not directly react with 2-mercaptoethanol, but, reacted in the form of an adduct with cobalt(II)histidine complex. During the course of the reaction the molecular oxygen is reduced to hydroxide ion while the cobalt(II)histidine complex was oxidized to cobalt(III)histidine while 2-mercaptoethanol is reduced into 2,2′-dithiodiethanol. The decrease in absorbance for the dioxygen complex was monitored spectrophotometrically and was observed that the values of rate constant increased with the increase in [2-mercaptoethanol]. The values of kobs also increased with increasing [NaOH]. Thus, from the results of these studies, mechanism of the reaction has been proposed. In addition, the values of various equilibrium constants and rate constants were also determined using nonlinear least square techniques.

Solvation of alanine and histidine functionalized carbon nanotubes in aqueous media: A Monte Carlo simulation study

In this research, the effect of adsorption of two amino acids on the solvation of carbon nanotubes is investigated. The complexes of β-Alanine and Histidine with armchair single wall carbon nanotube are studied by density functional theory. Then, the outcomes of Monte Carlo simulations of these nanotubes immersed in water to look at the effects of nanotube type on the solvation in water are reported. It is found that the binding energy of the interaction of β-Alanine with nanotube is larger than Histidine. The results of computer simulation in aqueous solution indicate that amino acid functionalization increases the intermolecular interactions of carbon nanotube and water. Computed solvation free energies are in this order: CNTAlanine>CNTHistidine>pure CNT.

Chromium-histidinate ameliorates productivity in heat-stressed Japanese quails through reducing oxidative stress and inhibiting heat-shock protein expression

An experiment was conducted to evaluate the effects of a histidine complex of chromium (chromium histidinate, CrHis) on egg production, lipid peroxidation and the expression of hepatic nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and heat-shock proteins (HSPs) in Japanese quails (Coturnix coturnix japonica) exposed to heat stress (HS).A total of 180 5-week-old female quails were reared either at 22°C for 24 h/d (thermoneutral, TN) or 34°C for 8 h/d (heat stress, HS) for 12 weeks. Birds in both environments were randomly given one of three diets: basal diet and basal diet supplemented with 400 or 800 µg of elemental Cr as CrHis per kg of diet. Blood, egg yolk and liver samples collected at the end of the trial were analysed to determine concentrations of cholesterol and malondialdehyde (MDA) and expressions of transcription and heat-shock proteins.Exposure to HS caused reductions in feed intake (−8.1%) and egg production (−15.8%), elevations in serum (14.8%) and egg-yolk (29.0%) cholesterol concentrations, decreases in serum (113%) and egg-yolk (73.0%) MDA concentrations and increases in the expressions of hepatic NF-κB (52.3%) and HSPs (averaging 53.6%).The effects of increasing supplemental CrHis on the response variables were more notable in the HS environment than in the TN environment. There were considerable improvements in feed intake and egg production, decreases in serum and egg-yolk cholesterol concentrations and suppressions in the expressions of hepatic nuclear protein and HSPs in response to increasing supplemental CrHis concentration in the diet of quails reared under the HS environment.In conclusion, supplemental CrHis improves productivity through alleviating oxidative stress and modulating the expressions of hepatic NF-κB and HSPs in heat-stressed quails.

Effects of nickel nutrition in the mineral form and complexed with histidine in the nitrogen metabolism of onion bulb

Excess accumulation of nitrate in edible plants particularly onion is a great concern for human health. In this experiment, we investigated the possibility of reducing nitrate accumulation in onion bulb by application of Ni. Two onion cultivars (Allium cepa L. cvs. Dorrcheh and Cebolla Valenciana) were supplied with three levels of Ni (0, 25, and 50 µM) in the form of synthetic Ni–histidine complex [Ni(His)2] and NiCl2. Addition of Ni significantly increased fresh bulb mass of onion cultivars. In ‘Valenciana’, increasing Ni concentration from 25 to 50 µM reduced fresh bulb mass while in ‘Dorrcheh’, no significant difference was found between 25 and 50 µM Ni treatments. Supplement with Ni resulted in lower accumulation of nitrate in onion bulb. This reduction was associated with higher activity of nitrate reductase (NR) and glutamine synthetase (GS). Onion plants supplied with Ni had higher concentration of ammonium and total N in their bulb compared with those unsupplied with Ni. The [Ni(His)2] complex was more effective than NiCl2 in improving yield, stimulating activity of NR and GS, and reducing nitrate concentration in onion. According to the results obtained, application of 25 µM Ni particularly in the form of [Ni(His)2] can be effective in reducing nitrate accumulation and enhancing health quality of onion.