Spectroscopic characterization of Phoenician-Punic coins

Sardinia hosted many Phoenician and Punic communities, as integrated forms of pacific cohabitation with the Lebanese merchants or actual colonies for the exploitation of the rich mines and wealthy coastal emporia under the Carthaginians (750-250 B.C.). One of their most important settlements is that of Mount Sirai, in the south west of the island, whose excavation revealed a complex structure of the site and allowed the discovery of excellent finds, as steles, everyday-life objects and tools, grave goods, amulets and coins. Punic coins were made by gold, electrum or, more commonly, by bronze. The first coin mintage from Carthage dates back to the IV century B.C. Whether the mintage was exclusive to Carthage or permitted outside the city too is still a matter of debate. There is the possibility that mintages were allowed in Sardinia (320-238 B.C. as well as in 216), in Spain (237-209 B.C.) and Southern Italy (216-203 B.C.). We have analyzed ten of these bronze coins (Fig. 1) to unveil the secrets of their mintage, origins and inner structure. Some traditional spectroscopic techniques such as X-ray diffraction (XRD) and fluorescence (XRF) have been used for this purpose, allowing us to learn about their mineral content (XRD) and elemental composition (XRF) [1,2]. Here we report about these findings

Microstructural features of human bones and funerary practices in Mount Sirai (Sardinia)

In the attempt to set up a useful methodology for the investigation of burned human remains in archaeological, anthropological and forensic fields, we decided to compare the most common protocols for the study of bone bioapatites (Fourier Transform Infrared spectroscopy, FT-IR, and X-ray Diffraction, XRD) to those deriving from the application of X-ray scattering techniques using synchrotron light. In this way, we expect to take advantage of the wider and more dynamic qualities of such a valuable tool in order to examine a higher number of samples in a very short time compared to the “traditional” techniques, meanwhile assessing its applicability in the archaeological field

Validation of protein models by a neural network approach

Background: The development and improvement of reliable computational methods designed to evaluate the quality of protein models is relevant in the context of protein structure refinement, which has been recently identified as one of the bottlenecks limiting the quality and usefulness of protein structure prediction. Results: In this contribution, we present a computational method (Artificial Intelligence Decoys Evaluator: AIDE) which is able to consistently discriminate between correct and incorrect protein models. In particular, the method is based on neural networks that use as input 15 structural parameters, which include energy, solvent accessible surface, hydrophobic contacts and secondary structure content. The results obtained with AIDE on a set of decoy structures were evaluated using statistical indicators such as Pearson correlation coefficients, Znat, fraction enrichment, as well as ROC plots. It turned out that AIDE performances are comparable and often complementary to available state-of-the-art learning-based methods. Conclusion: In light of the results obtained with AIDE, as well as its comparison with available learning-based methods, it can be concluded that AIDE can be successfully used to evaluate the quality of protein structures. The use of AIDE in combination with other evaluation tools is expected to further enhance protein refinement effort

A modeling study of alphaB-crystallin in complex with zinc for investigating the correlation between chaperone-like activity and exposure of hydrophobic surfaces

Three-dimensional models for alphaB-crystallin and its complex with zinc were obtained by molecular homology modeling and quantum mechanical calculations in order to explain the effect of the metal on the chaperone-like activity of alphaB-crystallin. In fact, measurements of the chaperone-like activity of alphaB-crystallin revealed that it is significantly increased in presence of the zinc. The theoretical models allowed us to estimate the increased exposition of hydrophobic residues caused by the presence of zinc, suggesting a relationship between structural changes and the increased chaperone-like activity

Binding free energy calculations of Adenosine Deaminase inhibitors

The interactions between four inhibitors and adenosine deaminase (ADA) were examined by calculating their binding free energies after molecular dynamics simulations. A bonded model was used to represent the electrostatic potentials of the zinc coordination site. The charge distribution of the model was derived by using a two-stage electrostatic potential fitting calculations. The calculated binding free energies are in good agreement with the experimental data and the ranking of binding affinities is well reproduced. Notably, our findings suggest that non-polar contributions play an important role for ADA-inhibitor interactions

Adducts and cyclometallated derivatives of palladium(II) with some 1,4-benzodiazepin-2-ones: crystal and molecular structure of <i>trans</i>-dichlorobis[7-chloro-1-(cyclopropylmethyl)-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepin-2-one] palladium(II)

The adducts trans-L2PdCl2 (1, L = Diazepam = 7- chloro-1,3-dihydro-1-methyl-5-phenyl-2H-1,4-benzodiazepin -2-one; 5, L = Prazepam = 7-chloro-1-(cyclopropylmethyl)- 1,3-dihydro-5-phenyl-2H-1,4-benzodiazepin-2-one) were prepared by reaction of PdCl2 or (PhCN)2PdCl2 with Diazepam and Prazepam, respectively. In the adducts, the benzodiazepines act as monodentate ligands through the 4-nitrogen atom, as shown by the structure of compound 5, determined by X-ray diffraction. Two crystalline modifications have been characterized: 5a, trans-(Prazepam)2PdCl2/CHCl3 1/1, monoclinic, space group P21/n, a = 11.996(4), b = 13.678(5), c = 12.717(3) Å, β = 98.83(2), Z = 2, R = 0.032; 5b, trans-(Prazepam)2PdCl2/CH2Cl2 1/1, monoclinic, space group P21/c, a = 14.074(3), b = 14.622(7), c = 19.360(10) Å, β = 100.04(3), Z = 4, R = 0.076. Cyclometallated derivatives [(L---H)PdCl]2, 2, L = Diazepam and 6, L = Prazepam, involving both C- and N-intramolecular coordination of the deprotonated ligands, have been obtained by reaction with Na2[PdCl4] in ethanol solution. In the dimeric species 2 and 6, the halide-bridge is easily split by reaction with Ph3P or Tl(acac), to give [(L---H)•(Ph3P)PdCl], (3, 7) and [(L---H)Pd(acac)] (4, 8) respectively

Structural Perturbation of alphaB-Crystallin by Zinc and Temperature related to its chaperonelike activity

alphaB-crystallin is a small heat shock protein that shows chaperone-like activity, as it protects the aggregation of denatured proteins. In this work, the possible relationships between structural characteristics and the biological activity of alphaB-crystallin were investigated on the native protein and on the protein undergoing the separate effects of metal ligation and temperature. The chaperone-like activity of alphaB-crystallin increased in the presence of zinc and when temperature was increased. By using fluorescent probes to monitor hydrophobic surfaces on alphaB-crystallin, it was found that exposed hydrophobic patches on the protein surface increased significantly both in the presence of zinc and when the temperature was raised from 25 to 37 degrees C. The zinc-induced increased exposure of lipophilic residues is in agreement with theoretical calculations performed on 3D-models of monomeric alphaB-crystallin, and may be significant to its increased biological activity

Structural perturbation of alphaB-crystallin by zinc and temperature related to its <i>chaperone-like</i> activity

αB-crystallin is a small heat shock protein that shows chaperone-like activity, as it protects the aggregation of denatured proteins. In this work, the possible relationships between structural characteristics and the biological activity of αB-crystallin were investigated on the native protein and on the protein undergoing the separate effects of metal ligation and temperature. The chaperone-like activity of αB-crystallin increased in the presence of zinc and when temperature was increased. By using fluorescent probes to monitor hydrophobic surfaces on αB-crystallin, it was found that exposed hydrophobic patches on the protein surface increased significantly both in the presence of zinc and when the temperature was raised from 25 to 37°C. The zinc-induced increased exposure of lipophilic residues is in agreement with theoretical calculations performed on 3D-models of monomeric αB-crystallin, and may be significant to its increased biological activity

Gold Clusters: From the Dispute on a Gold Chair to the Golden Future of Nanostructures

The present work opens with an acknowledgement to the research activity performed by Luciana Naldini while affiliated at the Università degli Studi di Sassari (Italy), in particular towards gold complexes and clusters, as a tribute to her outstanding figure in a time and a society where being a woman in science was rather difficult, hoping her achievements could be of inspiration to young female chemists in pursuing their careers against the many hurdles they may encounter. Naldini’s findings will be a key to introduce the most recent results in this field, showing how the chemistry of gold compounds has changed throughout the years, to reach levels of complexity and elegance that were once unimagined. The study of gold complexes and clusters with various phosphine ligands was Naldini’s main field of research because of the potential application of these species in diverse research areas including electronics, catalysis, and medicine. As the conclusion of a vital period of study, here we report Naldini’s last results on a hexanuclear cationic gold cluster, [(PPh3)6Au6(OH)2]2+, having a chair conformation, and on the assumption, supported by experimental data, that it comprises two hydroxyl groups. This contribution, within the fascinating field of inorganic chemistry, provides the intuition of how a simple electron counting may lead to predictable species of yet unknown molecular architectures and formulation, nowadays suggesting interesting opportunities to tune the electronic structures of similar and higher nuclearity species thanks to new spectroscopic and analytical approaches and software facilities. After several decades since Naldini’s exceptional work, the chemistry of the gold cluster has reached a considerable degree of complexity, dealing with new, single-atom precise, materials possessing interesting physico-chemical properties, such as luminescence, chirality, or paramagnetic behavior. Here we will describe some of the most significant contributions