Characterization of <Emphasis Type="Italic">Bacillus anthracis</Emphasis> arginase: effects of pH,temperature, and cell viability on metal preference

Background  

Arginase (RocF) hydrolyzes L-arginine to L-ornithine and urea. While previously characterized arginases have an alkaline pH optimum and require activation with manganese, arginase from Helicobacter pylori is optimally active with cobalt at pH 6. The arginase from Bacillus anthracis is not well characterized; therefore, this arginase was investigated by a variety of strategies and the enzyme was purified.     

Local and global modes of drug action in biochemical networks

Background  

It is becoming increasingly accepted that a shift is needed from the traditional target-based approach of drug development towards an integrated perspective of drug action in biochemical systems. To make this change possible, the interaction networks connecting drug targets to all components of biological systems must be identified and characterized.     

Synthesis, structure elucidation, DNA interaction, biological evaluation, and molecular docking of an isatin-derived tyramine bidentate Schiff base and its metal complexes

Abstract  

Three new transition metal complexes [CuL₂Cl₂], [NiL₂Cl₂], and [ZnL₂Cl₂], where L = Schiff base derived from isatin (1H-indole-2,3-dione) and tyramine (4-(2-aminoethyl)phenol), have been synthesized and characterized spectroscopically. The binding properties of these complexes with calf thymus DNA have been investigated by use of electronic absorption spectroscopy, viscosity measurement, cyclic voltammetry, and molecular docking analysis. Moreover, these complexes have been found to promote the cleavage of pUC19 DNA from the supercoiled form I to the open circular form II in the presence of hydrogen peroxide. The newly synthesized compounds were screened for antibacterial activity and subjected to molecular docking studies for inhibition of the enzyme Staphylococcus aureus sortase-A, which is a novel target for antibacterials.     

Palladium tetrazole–supported complex as an efficient catalyst for the Heck reaction

Abstract  

A tetrazole-supported polymeric ligand has been synthesized. The palladium complex derived from the polymeric material has been evaluated as a catalyst for the Heck reaction of aryl iodides and bromides with styrene to provide the corresponding products in high yields. The reaction proceeded smoothly in the presence of 1 mol% with respect to Pd of catalyst in DMF at 125 or 140 °C within 1–3 h. Recycling studies showed that the catalyst can be readily recovered and reused for several times without significant loss of catalytic activity.     

Aldimines of 5-aminouracil as reagents in 1,3-dipolar cycloaddition reaction

Abstract  

The condensation of 5-aminouracil with aromatic aldehydes gave the appropriate C-arylimines, which were used in [2+3] cycloaddition with nitrile oxides derived from 4-substituted benzaldoximes. As a result of the dipolar cycloaddition reaction several hitherto unknown 5-(3,5-diphenyl-1,2,4-oxadiazol-4(5H)-yl)pyrimidine-2,4(1H,3H)-diones have been obtained in satisfactory yields.     

Experimental and theoretical study of the complexation of the thallium cation with a hexaarylbenzene-based receptor

Abstract  

From extraction experiments in the two-phase water/nitrobenzene system and γ-activity measurements, the stability constant of a hexaarylbenzene-based receptor. Tl⁺ complex species dissolved in nitrobenzene saturated with water was determined. By using the quantum-mechanical density functional level of theory calculations, the most probable structure of this complex was derived.     

The yeast <Emphasis Type="Italic">ISN1</Emphasis> (<Emphasis Type="Italic">YOR155c</Emphasis>) gene encodes a new type of IMP-specific 5'-nucleotidase

Background  

The purine salvage enzyme inosine 5'-monophosphate (IMP)-specific 5'-nucleotidase catalyzes degradation of IMP to inosine. Although this enzymatic activity has been purified and characterized in Saccharomyces cerevisiae, the gene encoding IMP 5'-nucleotidase had not been identified.     

Mitochondrial oxidative phosphorylation in autosomal dominant optic atrophy

Background  

Autosomal dominant optic atrophy (ADOA), a form of progressive bilateral blindness due to loss of retinal ganglion cells and optic nerve deterioration, arises predominantly from mutations in the nuclear gene for the mitochondrial GTPase, OPA1. OPA1 localizes to mitochondrial cristae in the inner membrane where electron transport chain complexes are enriched. While OPA1 has been characterized for its role in mitochondrial cristae structure and organelle fusion, possible effects of OPA1 on mitochondrial function have not been determined.     

High affinity binding of hydrophobic and autoantigenic regions of proinsulin to the 70 kDa chaperone DnaK

Background  

Chaperones facilitate proper folding of peptides and bind to misfolded proteins as occurring during periods of cell stress. Complexes of peptides with chaperones induce peptide-directed immunity. Here we analyzed the interaction of (pre)proinsulin with the best characterized chaperone of the hsp70 family, bacterial DnaK.     

A combined extraction and DFT study on the complexation of H3O+ with a hexaarylbenzene-based receptor

Abstract  

By means of theoretical calculations at density functional level, the complex structure of a hexaarylbenzene-based receptor with Na⁺ was derived. In the resulting complex having C ₃ symmetry, the sodium cation synergistically interacts with the hydrophilic polar ethereal oxygen fence and with the central hydrophobic benzene bottom of the parent receptor via cation–π interaction.     

Thermophile-specific proteins: the gene product of <Emphasis Type="Italic">aq_1292</Emphasis> from <Emphasis Type="Italic">Aquifex aeolicus</Emphasis> is an NTPase

Background  

To identify thermophile-specific proteins, we performed phylogenetic patterns searches of 66 completely sequenced microbial genomes. This analysis revealed a cluster of orthologous groups (COG1618) which contains a protein from every thermophile and no sequence from 52 out of 53 mesophilic genomes. Thus, COG1618 proteins belong to the group of thermophile-specific proteins (THEPs) and therefore we here designate COG1618 proteins as THEP1s. Since no THEP1 had been analyzed biochemically thus far, we characterized the gene product of aq_1292 which is THEP1 from the hyperthermophilic bacterium Aquifex aeolicus (aaTHEP1).     

A combined experimental and theoretical study on the complexation of the ammonium ion with benzo-18-crown-6

Abstract  

From extraction experiments in the two-phase water/nitrobenzene system and γ-activity measurements, the stability constant of the benzo-18-crown-6–ammonium complex in nitrobenzene saturated with water was determined. Furthermore, the structure of the resulting complex was derived by means of theoretical calculations at the density functional level.     

Binding to DPF-motif by the POB1 EH domain is responsible for POB1-Eps15 interaction

Background  

Eps15 homology (EH) domains are protein interaction modules binding to peptides containing Asn-Pro-Phe (NPF) motifs and mediating critical events during endocytosis and signal transduction. The EH domain of POB1 associates with Eps15, a protein characterized by a striking string of DPF triplets, 15 in human and 13 in mouse Eps15, at the C-terminus and lacking the typical EH-binding NPF motif.     

Glycosylated VCAM-1 isoforms revealed in 2D western blots of HUVECs treated with tumoral soluble factors of breast cancer cells

Background  

Several common aspects of endothelial phenotype, such as the expression of cell adhesion molecules, are shared between metastasis and inflammation. Here, we analyzed VCAM-1 variants as biological markers of these two types of endothelial cell activation. With the combination of 2-DE and western blot techniques and the aid of tunicamycin, we analyzed N-glycosylation variants of VCAM-1 in primary human endothelial cells stimulated with either TNF or tumoral soluble factors (TSF's) derived from the human breast cancer cell line ZR75.30.     

A combined extraction and DFT study on the complexation of the silver cation with dibenzo-18-crown-6

Abstract  

Extraction experiments in the two-phase water/nitrobenzene system and γ-activity measurements were used to determine the stability constant of the dibenzo-18-crown-6·Ag⁺ complex species in nitrobenzene saturated with water. Furthermore, the structure of the resulting complex was derived by means of theoretical calculations at the density functional level.     

A strategy using NMR peptide structures of thromboxane A2 receptor as templates to construct ligand-recognition pocket of prostacyclin receptor

Background:  

Prostacyclin receptor (IP) and thromboxane A2 receptor (TP) belong to rhodopsin-type G protein-coupling receptors and respectively bind to prostacyclin and thromboxane A2 derived from arachidonic acid. Recently, we have determined the extracellular loop (eLP) structures of the human TP receptor by 2-D 1H NMR spectroscopy using constrained peptides mimicking the individual eLP segments. The studies have identified the segment along with several residues in the eLP domains important to ligand recognition, as well as proposed a ligand recognition pocket for the TP receptor.     

On the complexation of the sodium cation with beauvericin: experimental and theoretical study

Abstract  

From extraction experiments in the two-phase water/nitrobenzene system and γ-activity measurements, the stability constant of the beauvericin·Na⁺ complex species dissolved in nitrobenzene saturated with water was determined. By using quantum mechanical density functional level of theory (DFT) calculations, the most probable structure of this complex species was derived.     

The synthesis of new potential photosensitizers. 1. Mono-carboxylic acid derivatives of tetraphenylporphyrin

Abstract  

A series of mono-alkylcarboxylic acid derivatives of tetraphenylporphyrin have been prepared. All the porphyrins were completely characterized by use of mass, ¹H NMR, UV–visible, and fluorescence spectroscopy. Experimental log P were determined by use of reversed-phase thin-layer chromatography with use of log P _Rekker. These porphyrins are potential photosensitizers in photodynamic therapy.     

Cacao seeds are a "Super Fruit": A comparative analysis of various fruit powders and products

Background  

Numerous popular media sources have developed lists of "Super Foods" and, more recently, "Super Fruits". Such distinctions often are based on the antioxidant capacity and content of naturally occurring compounds such as polyphenols within those whole fruits or juices of the fruit which may be linked to potential health benefits. Cocoa powder and chocolate are made from an extract of the seeds of the fruit of the Theobroma cacao tree. In this study, we compared cocoa powder and cocoa products to powders and juices derived from fruits commonly considered "Super Fruits".     

Synthesis,spectral and structural studies of oxovanadium(IV/V) complexes derived from 2-hydroxyacetophenone-3-hydroxy-2-naphthoylhydrazone: polymorphs of oxovanadium(V) complex [VOL(OCH<Subscript>3</Subscript>)]

Abstract  

Oxovanadium(IV/V) complexes of 2-hydroxyacetophenone-3-hydroxy-2-naphthoylhydrazone (H₂L) have been synthesized and characterized. The complexes were characterized by elemental analyses, IR, electronic and EPR spectra. The oxovanadium(V) complex [VOL(OCH₃)] is crystallized in two polymorphic forms, denoted by 1a and 1b, with space groups Pn2₁a and P_[`1] P_{{\bar{1}}} , respectively. Both have distorted square pyramidal structures.