- Università degli Studi di Sassari, Dipartimento di Chimica e Farmacia, Via Vienna 2, Sassari
- 3495263986
- Massimiliano Peana is a researcher in Inorganic and Bioinorganic Chemistry at the Department of Chemistry and Pharmac... moreMassimiliano Peana is a researcher in Inorganic and Bioinorganic Chemistry at the Department of Chemistry and Pharmacy, University of Sassari, Sardinia, Italy, where he teaches inorganic and general chemistry, and sciences applied to cultural heritage. His current research interests are focused on metal interactions with peptides and proteins, molecular mechanisms of metal and metal nanoparticles related toxicity, carcinogenesis and neurodegeneration, and chelating agents for toxic metals. His research is based on the use of several spectroscopic techniques, especially NMR, which was deepened at CERM, Centre for Magnetic Resonance, University of Florence (2003–2007).edit
This work presents the simple and low cost synthesis of a new tripodal ligand, in which three units of kojic acid are coupled to a tris(2-aminoethyl)amine (tren) backbone molecule. The protonation equilibria, together with the complex... more
This work presents the simple and low cost synthesis of a new tripodal ligand, in which three units of kojic acid are coupled to a tris(2-aminoethyl)amine (tren) backbone molecule. The protonation equilibria, together with the complex formation equilibria of this ligand with Fe3+, Al3+, Cu2+ and Zn2+ ions were studied. The complementary use of potentiometric, spectrophotometric and NMR techniques, and of Density Functional Theory (DFT) calculations, has allowed a thorough characterization of the different species involved in equilibrium. The stability of the formed complexes with Fe3+ and Al3+ are high enough to consider the new ligand for further studies for its clinical applications as a chelating agent. Biodistribution studies were carried out to assess the capacity the ligand for mobilization of gallium in 67Ga-citrate injected mice. These studies demonstrated that this ligand efficiently chelates the radiometal in our animal model, which suggests that it can be a promising candidate as sequestering agent of iron and other hard trivalent metal ions. Furthermore, the good zinc complexation capacity appears as a stimulating result taking into a potential use of this new ligand in analytical chemistry as well as in agricultural and environmental applications.
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A B S T R A C T Ni(II) stimulates innate immunity via the direct binding to human Toll Like Receptor 4 (hTLR4), the bacterial lypopolysaccharide receptor. The binding is specific for humans and causes nickel contact allergy. The protein... more
A B S T R A C T Ni(II) stimulates innate immunity via the direct binding to human Toll Like Receptor 4 (hTLR4), the bacterial lypopolysaccharide receptor. The binding is specific for humans and causes nickel contact allergy. The protein sequence analysis of hTLR4 revealed that the ectodomain, the region supposed to coordinate the metal ions, contains a histidine-rich motif that is not conserved among all organisms. To elucidate the role of each histidine residue on the protein–nickel binding, we examined the formation of Ni(II) complexes with the model peptide NH 2-FQHSNRKQMSERSVFRSRRNRIYRDISHTHTR-COO − , which encompasses the sequence 429–460 of hTLR4. The amino acid sequence of the peptide has been modified by the substitution of some selected lipophilic residues (Leu and Phe) with hydrophilic residues (Arg), aiming at increasing the peptide hydro solubility of the protein fragment. Potentiometric, ultraviolet-visible (UV–vis), nuclear magnetic resonance (NMR) and circular dichroism (CD) measurements demonstrate that the non-conserved histidines in the ectodomain cooperate in metal coordination and consequently enable the activation of the molecular mechanism of nickel hypersensi-tivity reaction.
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5-Hydroxy-2-(hydroxymethyl)pyridin-4(1H)-one ligand, an iron chelator, was evaluated for its coordination ability toward Al(III), Cu(II) and Zn(II) ions by using potentiometric, NMR, EPR and UV–Vis techniques. The behavior of the ligand... more
5-Hydroxy-2-(hydroxymethyl)pyridin-4(1H)-one ligand, an iron chelator, was evaluated for its coordination ability toward Al(III), Cu(II) and Zn(II) ions by using potentiometric, NMR, EPR and UV–Vis techniques. The behavior of the ligand with the non-essential Al(III) ion has been examined, as well as its potential influence on the homeostatic equilibria of the essential Cu(II) and Zn(II) ions. Structural information on the complex formation equilibria have been obtained from 1D and 2D NMR study. The donor atoms involved in the coordination of Al(III), Cu(II) and Zn(II) ions are (O, O) the same as for Fe(III) at physiological pH value, even if from the complexation competition study the ligand appears to be more selective toward Fe(III) ions supporting that it can be used as an iron chelating agent. The involvement of N-donor atoms at high pH in Cu(II) coordination has been determined by using EPR and UV–Vis techniques.
Research Interests: Coordination Chemistry, Modelling Knowledge Coordination, NMR Spectroscopy, EPR Spectroscopy, Metal chelation, and 5 moreDetoxification, Inorganic Chemistry, Bioinorganic Chemistry, Coordination Chemistry, Nanotechnology, Material Science, Metallo-Organic Chemistry, Actinides, Thorium Compounds, Competitive Analysis, Heavy metals toxicity, and Chelation Therapy
Cadmium is not an essential element for humans, but instead its compounds are known for their toxicity. In addition to the risks for workers in industries that use cadmium, this metal can enter the food chain at different levels to be... more
Cadmium is not an essential element for humans, but instead its compounds are known for their toxicity. In addition to the risks for workers in industries that use cadmium, this metal can enter the food chain at different levels to be absorbed by the body, where it replaces other metals with similar chemical activity. This also applies to the cadmium inhaled via cigarette smoking. Thus, understanding the interactions between cadmium and biologically relevant molecules, such as amino acids, peptides, and proteins, is important, but it is also useful to study the chelating methods that can cure or alleviate acute or chronic cadmium poisoning cases. 111/113 Cd isotopes are used as NMR probes to determine the complex formation sites and geometry of metals in metalloproteins and metalloenzymes. This review provides a general introduction to the general properties of cadmium as well as the main uses of this metal, its compounds, and artifacts. The toxicity of cadmium in humans is also discussed and the most significant results regarding the interactions between cadmium and other potentially competing divalent metal ions with biological relevance, i.e. Fe(II), Zn(II), Mn(II), Ni(II), and Cu(II), and amino acids and peptides, particularly those containing histidine and/or thiolic groups, are collected. To the best of our knowledge, this is the most comprehensive summary reported for the speciation models of these systems. Distribution and competition diagrams were constructed to facilitate comparisons of the binding abilities of different metals with the same ligand (or vice versa) over a wide pH range and with different reagent concentrations and/or concentration ratios, thereby providing insights into the in vivo behavior both inside and outside cells where the pH and concentration can be very different. The vast topic of complexes with phy-tochelatins and metallothioneins is left for a more focused study. Finally, cadmium chelators with potential pharmacological applications are thoroughly reviewed.
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Silver coordination compounds with a number of different ligands (N-heterocyclic carbenes, phosphines, N-heterocycles and others) possess several properties, ranging from antibacterial, anti-inflammatory and antiseptic to antineoplastic... more
Silver coordination compounds with a number of different ligands (N-heterocyclic carbenes, phosphines, N-heterocycles and others) possess several properties, ranging from antibacterial, anti-inflammatory and antiseptic to antineoplastic activity. They also promise to be agents capable of overcoming drug resistance and beating antibiotic-resistant bacteria, fungi and parasites. In spite of the large volume of research undertaken in this area and the synthesis of several new silver complexes, most of them still remain in an academic research context and few have actually been approved for medical treatment of human diseases.
In this review we present an overview of this noble metal's active derivatives, properties, mode of action and potential uses with the aim of stimulating further evaluation of their potential clinical applications and therapeutic uses.
In this review we present an overview of this noble metal's active derivatives, properties, mode of action and potential uses with the aim of stimulating further evaluation of their potential clinical applications and therapeutic uses.
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A decapeptide, DEHGTAVMLK (DP1), and its random scrambled version, THMVLAKGED (DP2), have been studied for their interactions with manganese. The amino acid composition of the peptides was selected to include the majority of the most... more
A decapeptide, DEHGTAVMLK (DP1), and its random scrambled version, THMVLAKGED (DP2), have been studied for their interactions with manganese. The amino acid composition of the peptides was selected to include the majority of the most prevalent amino acids present in a Deinococcus radiodurans bacterium cell-free extract that contains components capable of conferring extreme resistance to ionizing radiation. The extract appears to be rich in Mn(II) complexes which seem to be responsible for protecting proteins from Reactive Oxygen Species damage. We focused our attention on the interaction of the decapeptides with Mn(II) ion with the aim of obtaining information on the possible complexes formed, by using NMR, EPR, and ESI-MS techniques.
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The ionization equilibria of a set of ortho, meta, and para substituted benzoic acids have been studied by spectrophotometric and potentiometric methods. A dual substituent analysis of the obtained ionization constants is presented,... more
The ionization equilibria of a set of ortho, meta, and para substituted benzoic acids have been studied by spectrophotometric and potentiometric methods. A dual substituent analysis of the obtained ionization constants is presented, according to the Swain and Lupton procedure. This analysis allows to assign the weight of field and resonance contributions to equilibrium constants and, furthermore, it greatly contributes to forecast the effect of substituents on other correlated properties.
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Angiogenin (Ang) is a potent angiogenic factor, strongly overexpressed in patients affected by different types of cancers. The specific Ang cellular receptors have not been identified, but it is known that Ang–actin interaction induces... more
Angiogenin (Ang) is a potent angiogenic factor, strongly overexpressed in patients affected by different types of cancers. The specific Ang cellular receptors have not been identified, but it is known that Ang–actin interaction induces changes both in the cell cytoskeleton and in the extracellular matrix. Most in vitro studies use the recombinant form (rAng) instead of the form that is normally present in vivo (" wild-type " , wt-Ang). The first residue of rAng is a methionine, with a free amino group, whereas wt-Ang has a glutamic acid, whose amino group spontaneously cyclizes in the pyro-glutamate form. The Ang biological activity is influenced by copper ions. To elucidate the role of such a free amino group on the protein–copper binding, we scrutinized the copper(II) complexes with the peptide fragments Ang(1–17) and AcAng(1–17), which encompass the sequence 1–17 of angiogenin (QDNSRYTHFLTQHYDAK-NH 2), with free amino and acetylated N-terminus, respectively. Potentiometric, ultraviolet-visible (UV-vis), nuclear magnetic resonance (NMR) and circular dichroism (CD) studies demonstrate that the two peptides show a different metal coordination environment. Confocal microscopy imaging of neuroblastoma cells with the actin staining supports the spectroscopic results, with the finding of different responses in the cytoskeleton organization upon the interaction, in the presence or not of copper ions, with the free amino and the acetylated N-terminus peptides.
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Gly-Ala-Asn-Asp-Cys-Gly-Amide, encompassing the sequence from residues 1164 to 1193 in the encoded protein from Parkinson's disease gene Park9 (YPk9), was studied for manganese and zinc binding. Manganese exposure is considered to be an... more
Gly-Ala-Asn-Asp-Cys-Gly-Amide, encompassing the sequence from residues 1164 to 1193 in the encoded protein from Parkinson's disease gene Park9 (YPk9), was studied for manganese and zinc binding. Manganese exposure is considered to be an environmental risk factor connected to PD and PD-like syndrome. Research into the genetic and environmental risk factors involved in disease susceptibility has recently uncovered a link existing between Park9 and manganese. It seems that manganese binding to Park9 (YPk9) protein is involved in the detoxification mechanism exerted by this protein against manganese toxicity. In this study, we used potentiometric, mono-and bi-dimensional (TOCSY, HSQC) NMR, EPR and ESI-MS measurements to analyze complex formation and metal binding sites in the peptide fragment. Presumably octahedral species, in which the Mn(II) ion was bound to oxygens of the carboxyl groups of Glu and Asp, and species where the involvement of sulfur from Cys and nitrogen from His residues, depending on the metal to ligand molar ratio, were detected for manganese coordination. Structural changes in the 30-amino acid fragment were triggered by Zn(II) interaction. A general decrease in the intensity of NMR signals was detected, suggesting the occurrence of chemical exchange among some coordinated species in an intermediate NMR timescale. The coordination may involve both S and N donor atoms from cysteine as well as histidine residues, together with O donor atoms from glutamic and aspartic residues.
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Superparamagnetic iron oxide nanoparticles (SPIONs) have been extensively investigated for many biomedical applications. A good quality functionalization that combines imaging goals with a high-level of biocompatibility remains one of the... more
Superparamagnetic iron oxide nanoparticles (SPIONs) have been extensively investigated for many biomedical applications. A good quality functionalization that combines imaging goals with a high-level of biocompatibility remains one of the challenges for particle translation into medical practice. Here, we focus on a new functionalization of SPIONs with cystine (Cy-SPIONs). Cystine is able to make SPIONs stable and dispersible in water and in culture cell media. New insights are provided into the biological and immune effects of Cy-SPIONs with a wide variety of standard and molecular assays to evaluate cytotoxicity, cell activation, cytokine release and the expression of 84 genes related to immune responses. A good immune biocompatibility of Cy-SPIONs on primary immune cells was found. The great potential of Cy-SPIONs for further in vivo studies and as contrast agents for magnetic resonance imaging (MRI) is highlighted. In addition, we also exploited ultrasonography, since it is a safer, less expensive and common imaging technology. The good echogenic properties of Cy-SPIONs in water and in whole blood are shown, both in vitro and in a phantom vein for bloodstream simulations. Our results open up a new scenario for future applications of cystine-functionalized SPIONs as immune-compatible ultrasound and MRI contrast agents.
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The ionization equilibria of a set of ortho, meta, and para substituted benzoic acids have been studied by spectrophotometric and potentiometric methods. A dual substituent analysis of the obtained ionization constants is presented,... more
The ionization equilibria of a set of ortho,
meta, and para substituted benzoic acids have been studied
by spectrophotometric and potentiometric methods. A dual
substituent analysis of the obtained ionization constants is
presented, according to the Swain and Lupton procedure.
This analysis allows to assign the weight of field and resonance
contributions to equilibrium constants and,
furthermore, it greatly contributes to forecast the effect of
substituents on other correlated properties.
meta, and para substituted benzoic acids have been studied
by spectrophotometric and potentiometric methods. A dual
substituent analysis of the obtained ionization constants is
presented, according to the Swain and Lupton procedure.
This analysis allows to assign the weight of field and resonance
contributions to equilibrium constants and,
furthermore, it greatly contributes to forecast the effect of
substituents on other correlated properties.
Research Interests:
The synthesis of 5-hydroxy-2-(hydroxymethyl)pyridin-4(1H)-one (P1) is presented, together with the evaluation of its coordination ability towards Fe 3+ , studied by combining chemical, computational, and animal approaches. The use of... more
The synthesis of 5-hydroxy-2-(hydroxymethyl)pyridin-4(1H)-one (P1) is presented, together with the evaluation of its coordination ability towards Fe 3+ , studied by combining chemical, computational, and animal approaches. The use of complementary analytical techniques has allowed to give evidence of the tautomeric changes of P1 as a function of pH, and to determine their influence on the coordinating ability of P1 towards Fe 3+. The pFe 3+ value 22.0 of P1-iron complexes is noticeable higher than that of deferiprone (20.6), one of the three clinical chelating agents in therapeutic use for iron overload diseases. This is due on one side to the tautomeric change to the catechol form, and on the other to the lower protonation constant of the OH group. Bio-distribution studies on mice allowed to confirm in vivo the efficacy of P1. Furthermore the coordinating ability toward Al 3+ , Cu 2+ and Zn 2+ has been studied to evaluate the possible use of P1 against a second toxic metal ion (Al 3+), and to envisage its potential influence on the homeostatic equilibria of essential metal ions. The chelating ability of P1 toward these last ions, not higher than that of the corresponding deferiprone, contributes to render P1 a more selective iron chelator.
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The conformational space sampled by the two-domain protein calmodulin has been explored by an approach based on four sets of NMR observables obtained on Tb(3+)- and Tm(3+)-substituted proteins. The observables are the pseudocontact shifts... more
The conformational space sampled by the two-domain protein calmodulin has been explored by an approach based on four sets of NMR observables obtained on Tb(3+)- and Tm(3+)-substituted proteins. The observables are the pseudocontact shifts and residual dipolar couplings of the C-terminal domain when lanthanide substitution is at the N-terminal domain. Each set of observables provides independent information on the conformations experienced by the molecule. It is found that not all sterically allowed conformations are equally populated. Taking the N-terminal domain as the reference, the C-terminal domain preferentially resides in a region of space inscribed in a wide elliptical cone. The axis of the cone is tilted by approximately 30 degrees with respect to the direction of the N-terminal part of the interdomain helix, which is known to have a flexible central part in solution. The C-terminal domain also undergoes rotation about the axis defined by the C-terminal part of the interdoma...
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Tavola Periodica degli Elementi Mod I - Introduzione al Corso Mod II - Nozioni di Chimica Parte 1 Mod II - Nozioni di Chimica Parte 2 Mod II - Nozioni di Chimica Parte 3 Mod III - Tecniche Analitiche Parte 1 Mod III - Tecniche... more
Tavola Periodica degli Elementi
Mod I - Introduzione al Corso
Mod II - Nozioni di Chimica Parte 1
Mod II - Nozioni di Chimica Parte 2
Mod II - Nozioni di Chimica Parte 3
Mod III - Tecniche Analitiche Parte 1
Mod III - Tecniche Analitiche Parte 2
Mod III - Tecniche Analitiche Parte 3
Mod IV - Materiali Lapidei
Mod IV - APPROFONDIMENTO - L’impatto dell’inquinamento atmosferico sui beni di interesse storico-artistico esposti all’aperto
Mod IV - Materiali Coloranti
Mod IV - APPROFONDIMENTO - Preparazione, usi e conseguenze di inchiostri antichi Metallo-Gallato.
Mod IV - Materiali Ceramici
Mod IV - Materiali Vetrosi
Mod IV - Materiali Metallici
Mod IV - Materiali Organici
Mod V - Autenticazione - Datazione
Mod V - Studi di Provenienza
Mod V - Conservazione e Restauro
Mod V - Informazioni Tecnologiche
Mod V - Informazioni Aggiuntive
Mod I - Introduzione al Corso
Mod II - Nozioni di Chimica Parte 1
Mod II - Nozioni di Chimica Parte 2
Mod II - Nozioni di Chimica Parte 3
Mod III - Tecniche Analitiche Parte 1
Mod III - Tecniche Analitiche Parte 2
Mod III - Tecniche Analitiche Parte 3
Mod IV - Materiali Lapidei
Mod IV - APPROFONDIMENTO - L’impatto dell’inquinamento atmosferico sui beni di interesse storico-artistico esposti all’aperto
Mod IV - Materiali Coloranti
Mod IV - APPROFONDIMENTO - Preparazione, usi e conseguenze di inchiostri antichi Metallo-Gallato.
Mod IV - Materiali Ceramici
Mod IV - Materiali Vetrosi
Mod IV - Materiali Metallici
Mod IV - Materiali Organici
Mod V - Autenticazione - Datazione
Mod V - Studi di Provenienza
Mod V - Conservazione e Restauro
Mod V - Informazioni Tecnologiche
Mod V - Informazioni Aggiuntive