Chiral Separation of Uncharged Pomalidomide Enantiomers Using Carboxymethyl‐β‐Cyclodextrin: A Validated Capillary Electrophoretic Method

The racemic mixture of pomalidomide (POM), a second‐generation immunomodulatory uncharged drug, was separated into enantiomers by capillary zone electrophoresis for the first time. Seven different chargeable cyclodextrin (CD) derivatives were screened as complexing agents and chiral selectors, investigating the stability of the POM‐CD inclusion complexes and their enantiodiscriminating capacities. Based on preliminary experiments, carboxymethyl‐β‐CD (CM‐β‐CD) was found to be the most effective chiral selector. Factors influencing enantioseparation were systematically optimized, using an orthogonal experimental design. Optimal parameters (background electrolyte [BGE]: 50 mM Tris‐acetate buffer, pH 6.5, containing 15 mM CM‐β‐CD; capillary temperature: 20°C; voltage applied +15 kV) allowed baseline separation of POM enantiomers with a resolution as high as 4.87. The developed method was validated, in terms of sensitivity (limit of detection and limit of quantification), linearity, accuracy, repeatability, and intermediate precision. Chirality 28:199–203, 2016. © 2015 Wiley Periodicals, Inc.     

Catalytic domain of MMP20 (Enamelysin) - the NMR structure of a new matrix metalloproteinase

The solution structure of the catalytic domain of MMP-20, a member of the matrix metalloproteinases family not yet structurally characterized, complexed with N-Isobutyl-N-(4-methoxyphenylsulfonyl)glycyl hydroxamic acid (NNGH), is here reported and compared with other MMPs-NNGH adducts. The backbone dynamic has been characterized as well. We have found that, despite the same fold and very high overall similarity, the present structure experiences specific structural and dynamical similarities with some MMPs and differences with others, around the catalytic cavity. The present solution structure, not only contributes to fill the gap of structural knowledge on human MMPs, but also provides further information to design more selective and efficient inhibitors for a specific member of this class of proteins.     

The different intermolecular interactions of the soluble copper-binding domains of the menkes protein, ATP7A

ATP7A is a P-type ATPase involved in copper(I) homeostasis in humans. It possesses a long N-terminal cytosolic tail containing six domains that are individually folded and capable of binding one copper(I) ion each. We investigated the entire N-terminal tail (MNK1-6) in solution by NMR spectroscopy and addressed its interaction with copper(I) and with copper(I)-HAH1, the physiological partner of ATP7A. At copper(I)-HAH1:MNK1-6 ratios of up to 3:1, thus encompassing the range of protein ratios in vivo, both the first and fourth domain of the tail formed a metal-mediated adduct with HAH1 whereas the sixth domain was simultaneously able to partly remove copper(I) from HAH1. These processes are not dependent on one another. In particular, formation of the adducts is not necessary for copper(I) transfer from HAH1 to the sixth domain. The present data, together with available in vivo studies, suggest that the localization of ATP7A between the trans-Golgi network and the plasma membrane may be regulated by the accumulation of the adducts with HAH1, whereas the main role of domains 5 and 6 is to assist copper(I) translocation.     

Ethnobotanical notes about some uses of medicinal plants in Alto Tirreno Cosentino area (Calabria, Southern Italy)

The present zootherapeutic study describes the traditional knowledge related to the use of different animals and animal-derived products as medicines by the Saharia tribe reside in the Shahabad and Kishanganj Panchayat Samiti's of Baran district of Rajasthan, India. A field survey was conducted from April to June 2006 by performing interview through structured questionnaire with 21 selected respondents, who provided information regarding use of animals and their products in folk medicine. A total of 15 animal species were recorded and they are used for different ethnomedical purposes, including cough, asthma, tuberculosis, paralysis, earache, herpes, weakness, muscular pain etc. The zootherapeutic knowledge was mostly based on domestic animals, but some protected species like the peacock (Pavo cristatus,), hard shelled turtle (Kachuga tentoria), sambhar (Cervus unicolor) were also mentioned as medicinal resources. We would suggest that this kind of neglected traditional knowledge should be included into the strategies of conservation and management of faunistic resources. Further studies are required for experimental validation to confirm the presence of bioactive compounds in these traditional remedies and also to emphasize more sustainable use of these resources.     

Supramolecular structure of self-assembling alamethicin analog studied by ESR and PELDOR

Three analogs of alamethicin F50/5, labelled with the TOAC (='2,2,6,6-tetramethylpiperidin-1-oxyl-4-amino-4-carboxylic acid') spin label at positions 1 (Alm1), 8 (Alm8), and 16 (Alm16), resp., were studied by Electron-Spin-Resonance (ESR) and Pulsed Electron-Electron Double-Resonance (PELDOR) techniques in solvents of different polarity to investigate the self-assembly of amphipathic helical peptides in membrane-mimicking environments. In polar solvents, alamethicin forms homogeneous solutions. In the weakly polar chloroform/toluene 1 : 1 mixture, however, this peptide forms aggregates that are detectable at 293 K by ESR in liquid solution, as well as by PELDOR in frozen, glassy solution at 77 K. In liquid solution, free alamethicin molecules and their aggregates show rotational-mobility correlation times tau(r) of 0.87 and 5.9 ns, resp. Based on these values and analysis of dipole-dipole interactions of the TOAC labels in the aggregates, as determined by PELDOR, the average number N of alamethicin molecules in the aggregates is estimated to be less than nine. A distance-distribution function between spin labels in the supramolecular aggregate was obtained. This function exhibits two maxima: a broad one at a distance of 3.0 nm, and a wide one at a distance of ca. 7 nm. A molecular-dynamics (MD)-based model of the aggregate, consisting of two parallel tetramers, each composed of four molecules arranged in a 'head-to-tail' fashion, is proposed, accounting for the observed distances and their distribution.     

The functions of Sco proteins from genome-based analysis

Sco proteins are widespread proteins found in eukaryotic as well as in many prokaryotic organisms. The 3D structure of representatives from human, yeast, and Bacillus subtilis has been determined, showing a thioredoxin-like fold. Sco proteins have been implicated mainly as copper transporters involved in the assembly of the CuA cofactor in cytochrome c oxidase. Some mutations have been identified in humans that lead to defective cytochrome c oxidase formation and thus to fatal illnesses. However, it appears that the physiological function of Sco proteins goes beyond assembly of the CuA cofactor. Extensive analysis of completely sequenced prokaryotic genomes reveals that 18% of them contain either Sco proteins but not CuA-containing proteins or vice versa. In addition, in several cases, multiple Sco-encoding genes occur even if only a single potential Sco target is encoded in the genome. Genomic context analysis indeed points to a more general role for Sco proteins in copper transport, also to copper enzymes lacking a CuA cofactor. To obtain further insight into the possible role of Sco in the assembly of other cofactors, a search for Cox11 proteins, which are important for CuB biosynthesis, was also performed. A general framework for the action of Sco proteins is proposed, based on the hypothesis that they can couple metal transport and thiol/disulfide-based oxidoreductase activity, as well as select between either of these two cellular functions. This model reconciles the variety of experimental observations made on these proteins over the years, and can constitute a basis for further studies.     

Quantifying personal exposure to air pollution from smartphone‐based location data

Personal exposure assessment is a challenging task that requires both measurements of the state of the environment as well as the individual's movements. In this paper, we show how location data collected by smartphone applications can be exploited to quantify the personal exposure of a large group of people to air pollution. A Bayesian approach that blends air quality monitoring data with individual location data is proposed to assess the individual exposure over time, under uncertainty of both the pollutant level and the individual location. A comparison with personal exposure obtained assuming fixed locations for the individuals is also provided. Location data collected by the Earthquake Network research project are employed to quantify the dynamic personal exposure to fine particulate matter of around 2500 people living in Santiago (Chile) over a 4‐month period. For around 30% of individuals, the personal exposure based on people movements emerges significantly different over the static exposure. On the basis of this result and thanks to a simulation study, we claim that even when the individual location is known with nonnegligible error, this helps to better assess personal exposure to air pollution. The approach is flexible and can be adopted to quantify the personal exposure based on any location‐aware smartphone application.     

Ameliorating effect of lipo-ATRA treatment on the expression of TIG3 and its suppressing effect on PPARγ gene expression in lung cancer animal model

Vitamin D₃ deficiency was found to be tightly linked to many health problems including metabolic syndrome, cancer, cardiovascular diseases, and type 2 diabetes mellitus. In our study, we tested the possible antidiabetic effects of one of vitamin D₃ analogs, alfacalcidol, solely or in a combination with metformin on type 2 diabetic rats. Type 2 diabetic model rats were induced by feeding high-fat diet for 4 weeks followed by intraperitoneal injection of streptozotocin. In addition to the control group, the diabetic rats were divided into four groups: untreated, metformin-treated, alfacalcidol-treated, and combination-treated group (metformin?+?alfacalcidol) for 4 weeks. The level of fasting blood glucose, fasting serum insulin, homeostatic model of insulin resistance, serum lipid profile, liver enzymes, calcium, phosphorus, and 25-hydroxyvitamin D₃ were also determined. Besides, sterol regulatory element binding protein-1c (SREBP-1c) and vitamin D receptors (VDR) gene expression at mRNA and protein levels were evaluated. The level of significance was fixed at P?≤?0.05 for all statistical tests. Alfacalcidol, solely or combined with metformin, significantly ameliorated glucose homeostasis and lipid profile parameters (P?<?0.001) with a neutral effect on calcium and phosphorus levels. Significant downregulation of mRNA expression of SREBP-1c in the liver, white as well as brown adipose tissues (P?<?0.001) and different patterns of mRNA expression of VDR gene in pancreas and white adipose tissue were observed in rats treated with alfacalcidol solely or in combination with metformin. Vitamin D₃ analogs can modulate glucose parameters and lipid metabolism in a diabetic rat model and it provides additional protective effects when combined with metformin.

     

Dynamics of Fusarium solani cutinase investigated through structural comparison among different crystal forms of its variants

In characterizing mutants and covalently inhibited complexes of Fusarium solani cutinase, which is a 197-residue lipolytic enzyme, 34 variant structures, crystallizing in 8 different crystal forms, have been determined, mostly at high resolution. Taking advantage of this considerable body of information, a structural comparative analysis was carried out to investigate the dynamics of cutinase. Surface loops were identified as the major flexible protein regions, particularly those forming the active-site groove, whereas the elements constituting the protein scaffold were found to retain the same conformation in all the cutinase variants studied. Flexibility turned out to be correlated with thermal motion. With a given crystal packing environment, a high flexibility turned out to be correlated with a low involvement in crystal packing contacts. The high degree of crystal polymorphism, which allowed different conformations with similar energy to be detected, made it possible to identify motions which would have remained unidentified if only a single crystal form had been available. Fairly good agreement was found to exist between the data obtained from the structural comparison and those from a molecular dynamics (MD) simulation carried out on the native enzyme. The crystallographic approach used in this study turned out to be a suitable tool for investigating cutinase dynamics. Because of the availability of a set of closely related proteins in different crystal environments, the intrinsic drawback of a crystallographic approach was bypassed. By combining several static pictures, the dynamics of the protein could be monitored much more realistically than what can be achieved on the basis of static pictures alone. Proteins 26:442–458 © 1996 Wiley-Liss, Inc.