Uno Ferro,a de novo Designed Protein,Binds Transition Metals with High Affinity and Stabilizes Semiquinone Radical Anion

Metalloenzymes often utilize radicals in order to facilitate chemical reactions. Recently, DeGrado and co-workers have discovered that model proteins can efficiently stabilize semiquinone radical anion produced by oxidation of 3,5-di-tert-butylcatechol (DTBC) in the presence of two zinc ions. Here, we show that the number and the nature of metal ions have relatively minor effect on semiquinone stabilization in model proteins, with a single metal ion being sufficient for radical stabilization. The radical is stabilized by both metal ion, hydrophobic sequestration, and interactions with the hydrophilic residues in the protein interior resulting in a remarkable, nearly 500 mV change in the redox potential of the SQ ^{. −}/catechol couple compared to bulk aqueous solution. Moreover, we have created 4G-UFsc, a single metal ion-binding protein with pm affinity for zinc that is higher than any other reported model systems and is on par with many natural zinc-containing proteins. We expect that the robust and easy-to-modify DFsc/UFsc family of proteins will become a versatile tool for mechanistic model studies of metalloenzymes.     

Biomimetic and Biocatalytic Synthesis of Bruceol

The first total synthesis of bruceol has been achieved using a biomimetic cascade cyclization initiated by a stereoselective Jacobsen–Katsuki epoxidation (and kinetic resolution) of racemic protobruceol‐I. A bacterial cytochrome P450 monooxygenase was also found to catalyze the conversion of protobruceol‐I into bruceol. The first full analysis of the NMR data of natural bruceol suggested that “isobruceol” was a previously unrecognized natural product also isolated from Philotheca brucei. This was confirmed by the re‐isolation, synthesis, and X‐ray analysis of isobruceol. In total, eight stereoisomers and structural isomers of bruceol have been synthesized in a highly divergent approach.     

Competition between supernucleation and plasticization in the crystallization and rheological behavior of PCL/CNT‐based nanocomposites and nanohybrids

PCL was blended with pristine multiwalled carbon nanotubes (MWCNT) and with a nanohybrid obtained from the same MWCNT but grafted with low molecular weight PCL, employing concentrations of 0.25 to 5 wt % of MWCNT and MWCNT‐g‐PCL. Excellent CNT dispersion was found in all samples leading to supernucleation of both nanofiller types. Nanohybrids with 1 wt % or less MWCNTs crystallize faster than nanocomposites (due to supernucleation), while the trend eventually reverses at higher nanotubes content (because of plasticization). Rheological results show that yield‐like behavior develops in both nanocomposites, even for the minimum content of carbon nanotubes. In addition, the MWCNT‐g‐PCL family, when compared with the neat polymer, exhibits lower values of viscosity and modulus in oscillatory shear, and higher compliance in creep. These rheological differences are discussed in terms of the plasticization effect caused by the existence of low molecular weight free and grafted PCL chains in the nanohybrids. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 1310–1325     

Applications of deuterium oxide in human health

The main aim goal of this review was to gather information about recent publications related to deuterium oxide (D₂O), and its use as a scientific tool related to human health. Searches were made in electronic databases Pubmed, Scielo, Lilacs, Medline and Cochrane. Moreover, the following patent databases were consulted: EPO (Espacenet patent search), USPTO (United States Patent and Trademark Office) and Google Patents, which cover researches worldwide related to innovations using D₂O.     

Redox Mediated Synthesis of Ag-CuO Hybrid Nanoparticles – DNA/BSA Binding Studies and in vitro Evaluation of Anti-cancer Activity on MCF-7 Cancer Cell Line

We herein report a nanoparticle-directed therapeutic approach to breast cancer using Ag-CuO hybrid nanoparticles. The nanoparticles were synthesized through redox-mediated process involving reduction of silver ion on the surface of Cu₂O nanostructures. Structural, microstructural and optical characterization were carried out and the hybrid nanoparticles were found to be phase pure with crystallite size between 100–200 nm and the absorption due to surface plasmon resonance from silver was observed around 460 nm. The binding affinities of the hybrid nanoparticles with the plasma protein BSA and calf thymus DNA were studied and the respective binding constants were found to be 5.1 × 10⁴ and 1.12 × 10⁵ M⁻¹ showing appreciable binding affinity of the substrate. The cytotoxicity of the as-synthesized hybrid nanoparticles induced in breast cancer cells was evaluated in vitro and the obtained results demonstrates the potential anti-cancer activity of the Ag-CuO hybrid nanoparticles against the MCF-7 breast cancer cell line.     

Carleson Measures for Non-negative Subharmonic Functions on Homogeneous Trees

Potential Analysis - In Cohen et al. (Potential Anal. 44(4), 745–766, 2016), we introduced several classes of Carleson-type measures with respect to a radial reference measure σ on a...     

Synthesis of Oligonucleotides Containing the N6-(2-Deoxy-α,β-d-erythropentofuranosyl)-2,6-diamino-4-hydroxy-5-formamidopyrimidine (Fapy⋅dG) Oxidative Damage Product Derived from 2′-Deoxyguanosine

N⁶-(2-Deoxy-α,β-d -erythropentofuranosyl)-2,6-diamino-4-hydroxy-5-formamidopyrimidine (Fapy⋅dG) is a major DNA lesion produced from 2′-deoxyguanosine under oxidizing conditions. Fapy ⋅ dG is produced from a common intermediate that leads to 7,8-dihydro-8-oxo-2′-deoxyguanosine (8-OxodGuo), and in greater quantities in cells. The impact of Fapy ⋅ dG on DNA structure and function is much less well understood than that of 8-OxodGuo. This is largely due to the significantly greater difficulty in synthesizing oligonucleotides containing Fapy ⋅ dG than 8-OxodGuo. We describe a synthetic approach for preparing oligonucleotides containing Fapy ⋅ dG that will facilitate intensive studies of this lesion in DNA. A variety of oligonucleotides as long as 30 nucleotides are synthesized. We anticipate that the chemistry described herein will provide an impetus for a wide range of studies involving Fapy ⋅ dG.     

A Lamellar MWW Zeolite With Silicon and Niobium Oxide Pillars: A Catalyst for the Oxidation of Volatile Organic Compounds

In this work, an MWW-type zeolite with pillars containing silicon and niobium oxide was synthesized to obtain a hierarchical zeolite. The effect of niobium insertion in the pillaring process was determined by combining a controllable acidity and accessibility in the final material. All pillared materials had niobium occupying framework positions in pillars and extra-framework positions. The pillared material, Pil-Nb-4.5 with 4.5 wt % niobium, did not compromise the mesoporosity formed by pillaring, while the increase of niobium in the structure gradually decreased the mesoporosity and ordering of lamellar stacking. The morphology of the pillared zeolites and the niobium content were found to directly affect the catalytic activity. Specifically, we report on the activity of the MWW-type zeolites with niobium catalyzing the gas-phase oxidation of volatile organic compounds (VOCs), which is an important reaction for clean environmental. All produced MWW-type zeolites with niobium were catalytically active, even at low temperatures and low niobium loading, and provided excellent conversion efficiencies.