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.

Cremation practices coexisting at the S'Illot des Porros Necropolis during the Second Iron Age in the Balearic Islands (Spain).

The necropolis of S'Illot des Porros, one of the most important prehistoric funerary sites of the Balearic Islands (Spain), was in use from the VIth and Vth century BCE until the Ist century CE. Located in a funerary area which contains two cementeries and one sanctuary, this site is constituted by three funerary chambers named A, B and C, respectively. Investigations on all the human burnt bone remains of the chambers, carried out mainly by the X-ray diffraction and supplemented in some cases by Fourier Transform Infrared spectroscopy pointed to the simultaneous use of inhumation and cremation funerary rites, probably due to existing social differences.

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.

Structural perturbation of alphaB-crystallin by zinc and temperature related to its chaperone-like 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.

Temperature dependence of chaperone-like activity and oligomeric state of alphaB-crystallin.

The chaperone-like activity and the oligomeric state of alphaB-crystallin were studied at different temperatures and in the presence of urea and thiocyanate. The activity, assessed measuring the ability of alphaB-crystallin to prevent the aggregation of denatured insulin, strongly depends on temperature. While a significant activity increase was detected at 42 degrees C, the presence of urea and thiocyanate does not affect the protein activity in an irreversible way.

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.

A modeling study of alphaB-crystallin in complex with zinc for seeking of correlations 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.

Effects of divalent metal ions on the alphaB-crystallin chaperone-like activity: spectroscopic evidence for a complex between copper(II) and protein.

AlphaB-crystallin is a small heat shock protein, showing chaperone-like activity, that is expressed in the lens and in several other tissues. The role of some metal ions in the alphaB-crystallin biology starts to be well documented. In some neuro-degenerative pathologies, like Parkinson and Alzheimer's diseases, alphaB-crystallin is expressed at high levels.

Glucose oxidase catalyses the reduction of O2 to H2O2 in the presence of irradiated TiO2 and isopropyl alcohol.

Catalytic amounts of glucose oxidase from Aspergillus niger (GO) are active in the reduction of O2 to H2O2 in the presence of irradiated suspensions of TiO2 and isopropyl alcohol as electron donor. An explanation of this behaviour is given on the basis of the ability of the enzyme to capture electrons from the photoexcited TiO2 instead of its natural substrate, glucose. This process has a marked positive effect on both the oxidation of isopropyl alcohol to acetone and the formation of radical intermediates, which have been detected, for the first time, by EPR-spin trapping investigation.