Structural Flexibility and Disassembly Kinetics of Single Ferritin Molecules Using Optical Nanotweezers.

Ferritin, a spherical protein shell assembled from 24 subunits, functions as an efficient iron storage and release system through its channels. Understanding how various chemicals affect the structural behavior of ferritin is crucial for unravelling the origins of iron-related diseases in living organisms including humans. In particular, the influence of chemicals on ferritin's dynamics and iron release is barely explored at the single-protein level.

2'-F labelling of ribose in RNAs: a tool to analyse RNA/protein interactions by NMR in physiological conditions.

Protein-RNA interactions are central to numerous cellular processes. In this work, we present an easy and straightforward NMR-based approach to determine the RNA binding site of RNA binding proteins and to evaluate the binding of pairs of proteins to a single-stranded RNA (ssRNA) under physiological conditions, in this case in nuclear extracts. By incorporation of a F atom on the ribose of different nucleotides along the ssRNA sequence, we show that, upon addition of an RNA binding protein, the intensity of the F NMR signal changes when the F atom is located near the protein binding site.

FluoroTensor: Identification and tracking of colocalised molecules and their stoichiometries in multi-colour single molecule imaging via deep learning.

The identification of photobleaching steps in single molecule fluorescence imaging is a well-established procedure for analysing the stoichiometries of molecular complexes. Nonetheless, the method is challenging with protein fluorophores because of the high levels of noise, rapid bleaching and highly variable signal intensities, all of which complicate methods based on statistical analyses of intensities to identify bleaching steps. It has recently been shown that deep learning by convolutional neural networks can yield an accurate analysis with a relatively short computational time.

Structural insights into the complex of oncogenic KRas4B and Rgl2, a RalA/B activator.

About a quarter of total human cancers carry mutations in Ras isoforms. Accumulating evidence suggests that small GTPases, RalA, and RalB, and their activators, Ral guanine nucleotide exchange factors (RalGEFs), play an essential role in oncogenic Ras-induced signalling. We studied the interaction between human KRas4B and the Ras association (RA) domain of Rgl2 (Rgl2), one of the RA-containing RalGEFs.

Surface Passivation with a Perfluoroalkane Brush Improves the Precision of Single-Molecule Measurements.

Single-molecule imaging is invaluable for investigating the heterogeneous behavior and interactions of biological molecules. However, an impediment to precise sampling of single molecules is the irreversible adsorption of components onto the surfaces of cover glasses. This causes continuous changes in the concentrations of different molecules dissolved or suspended in the aqueous phase from the moment a sample is dispensed, which will shift, over time, the position of chemical equilibria between monomeric and multimeric components.

LED-driven controlled deposition of Ni onto TiO for visible-light expanded conversion of carbon dioxide into C-C alkanes.

Photocatalytic gas-phase hydrogenation of CO into alkanes was achieved over TiO-supported Ni nanoparticles under LED irradiation at 365 nm, 460 nm and white light. The photocatalysts were prepared using photo-assisted deposition of Ni salts under LED irradiation at 365 nm onto TiO P25 nanoparticles in methanol as a hole scavenger. This procedure yielded 2 nm Ni particles decorating the surface of TiO with a nickel mass content of about 2%.

Silver-Copper Oxide Heteronanostructures for the Plasmonic-Enhanced Photocatalytic Oxidation of N-Hexane in the Visible-NIR Range.

Volatile organic compounds (VOCs) are recognized as hazardous contributors to air pollution, precursors of multiple secondary byproducts, troposphere aerosols, and recognized contributors to respiratory and cancer-related issues in highly populated areas. Moreover, VOCs present in indoor environments represent a challenging issue that need to be addressed due to its increasing presence in nowadays society. Catalytic oxidation by noble metals represents the most effective but costly solution.

Cleavable and thermo-responsive hybrid nanoparticles for on-demand drug delivery.

By combining the photothermal ability of copper sulphide nanoparticles (NPs) upon excitation with Near Infrared (NIR) Light and the thermo-responsive properties of the homemade oligo (ethylene glycol) methyl ether methacrylate copolymer we have obtained fragmentable nanocomposites able to release a carried drug on-demand after NIR-light triggering. A complete physico-chemical characterization of the resulting nanoparticles has been carried out and their degradation assessed at different temperatures. Herein, we have also evaluated the drug loading capacity of those nanoparticles and the temperature dependence in their drug release kinetics using bupivacaine hydrochloride as a model drug.

Supramolecular transcription of guanosine monophosphate into mesostructured silica.

There is large interest in replicating biological supramolecular structures in inorganic materials that are capable of mimicking biological properties. The use of 5-guanosine monophosphate in the presence of Na(+) and K(+) ions as a supramolecular template for the synthesis of well-ordered mesostructured materials is reported here. Mesostructured particles with the confined template exhibit high structural order at both meso- and atomic scales, with a lower structural symmetry in the columnar mesophase.

Photochemical strategies for the seed-mediated growth of gold and gold-silver nanoparticles.

Gold nanoparticles (AuNP) can be used as seeds for the synthesis of larger AuNP of controllable size with narrow size distribution by photochemical reduction of additional Au(III) using water-soluble benzoins or H(2)O(2) as sources of reducing radicals. Further, beyond simply enlarging the AuNP, it is possible to add a shell of another metal, such as silver, leading to Au/Ag core-shell structures with controllable dimensions for both core and shell. This strategy illustrates the fine spatial and temporal control achievable using clean photochemical techniques without the addition of hard surface ligands often necessary to control the size and structure of gold-silver nanostructures.

Ultraclean derivatized monodisperse gold nanoparticles through laser drop ablation customization of polymorph gold nanostructures.

We report a novel nanosecond laser ablation synthesis for spherical gold nanoparticles as small as 4 nm in only 5 s (532 nm, 0.66 J/cm(2)), where the desired protecting agent can be selected in a protocol that avoids repeated sample irradiation and undesired exposure of the capping agent during ablation. This method takes advantage of the recently developed synthesis of clean unprotected polymorph and polydisperse gold nanostructures using H(2)O(2) as a reducing agent.

High-temperature organic reactions at room temperature using plasmon excitation: decomposition of dicumyl peroxide.

Photoexcitation of gold nanoparticles in their plasmon transition around 530 nm provides the means to carry high-energy reactions at room temperature. In the case of dicumyl peroxide (with activation energy of 34.3 kcal/mol) the reaction occurs in less than 1 min under 532 nm laser excitation.