Structural Analysis and Substrate Specificity of D-Carbamoylase from .

The synthesis of enantiomeric forms of D-amino acids can be achieved by a two-step "hydantoinase process" based on the sequential catalysis of substrates by specific enzymes, D-carbamoylase and D-hydantoinase. Here, we describe the structural features of D-carbamoylase from , the encoded gene of which was chemically synthesized and cloned into . A significant fraction of the overexpressed recombinant protein forms insoluble inclusion bodies, which are partially converted to a soluble state upon treatment with N-lauroylsarcosine or upon incubation of cells at 28 °C.

Structural and biochemical characterisation of the N-carbamoyl-β-alanine amidohydrolase from Rhizobium radiobacter MDC 8606.

N-carbamoyl-β-alanine amidohydrolase (CβAA) constitutes one of the most important groups of industrially relevant enzymes used in the production of optically pure amino acids and derivatives. In this study, a CβAA-encoding gene from Rhizobium radiobacter strain MDC 8606 was cloned and overexpressed in Escherichia coli. The purified recombinant enzyme (RrCβAA) showed a specific activity of 14 U·mg using N-carbamoyl-β-alanine as a substrate with an optimum activity at 55 °C and pH 8.

Incidence and Risk Factors for Acute Kidney Injury and Its Effect on Mortality in Patients Hospitalized From COVID-19.

Objective: To determine the incidence of and risk factors for the development of acute kidney injury (AKI) and investigate the association between AKI and mortality in patients hospitalized with coronavirus disease 2019 (COVID-19) infection.

Patients And Methods: This retrospective case series includes the first 370 patients consecutively hospitalized with confirmed COVID-19 illness between March 10, 2020, and May 13, 2020, at a 242-bed teaching hospital. To determine independent associations between demographic factors, comorbid conditions, and AKI incidence, multivariable logistic regression models were used to estimate odds ratios adjusted for clinical covariates.

Rational Engineering of the Substrate Specificity of a Thermostable D-Hydantoinase (Dihydropyrimidinase).

D-hydantoinases catalyze an enantioselective opening of 5- and 6-membered cyclic structures and therefore can be used for the production of optically pure precursors for biomedical applications. The thermostable D-hydantoinase from ATCC 31783 is a manganese-dependent enzyme and exhibits low activity towards bulky hydantoin derivatives. Homology modeling with a known 3D structure (PDB code: 1K1D) allowed us to identify the amino acids to be mutated at the substrate binding site and in its immediate vicinity to modulate the substrate specificity.

Targeting Degradation of EGFR through the Allosteric Site Leads to Cancer Cell Detachment-Promoted Death.

Targeting epidermal growth factor receptor (EGFR) with tyrosine kinase inhibitors (TKI) has been widely exploited to disrupt aberrant phosphorylation flux in cancer. However, a bottleneck of potent TKIs is the acquisition of drug resistance mutations, secondary effects, and low ability to attenuate tumor progression. We have developed an alternative means of targeting EGFR that relies on protein degradation through two consecutive routes, ultimately leading to cancer cell detachment-related death.

Novel Methicillin-Resistant CC8 Clone Identified in a Hospital Setting in Armenia.

Whole-genome sequencing (WGS) of methicillin-resistant (MRSA) has been sparse in low- and middle-income countries, therefore, its population structure is unknown for many regions. We conducted a pilot surveillance of MRSA in the maternity ward of a teaching hospital in Armenia, to characterize the genotypes of circulating MRSA clones. In total, 10 MRSA isolates from a hospital environment ( = 4) and patients ( = 6) were recovered between March and May 2015 and April and May 2016, respectively.

Detection of diverse genotypes of Methicillin-resistant from hospital personnel and the environment in Armenia.

Background: Methicillin-resistant (MRSA) is a public health concern internationally. Studies examining a range of cohorts have been reported from various regions of the world, but little is known about the molecular epidemiology of MRSA in Armenia.

Methods: Between May and September 2013, twenty isolates of methicillin-resistant (MRSA; positive) were recovered from hospital personnel ( = 10; 9 females, 1 male) and environmental sites ( = 10) in the maternity ward of one of the teaching hospitals in Armenia.

[Catalytic properties of aminoacylase of strain Rhodococcus armeniensis AM6.1].

Studies of substrate specificity revealed that the D-aminoacylase of Rhodococcus armeniensis AM6.1 strain exhibits absolute stereospecificity to the D-stereoisomers of N-acetyl-amino acids. The enzyme is the most active reacted with N-acetyl-D-methionine, as well as with aromatic and hydrophobic N-acetylamino acids and interacts weakly with the basic substrates.

Activation of EGFR by small compounds through coupling the generation of hydrogen peroxide to stable dimerization of Cu/Zn SOD1.

Activation of cell signaling by reactive chemicals and pollutants is an important issue for human health. It has been shown that lipophilic nitro-benzoxadiazole (NBD) compounds rapidly move across the plasma membrane and enhance Epidermal Growth Factor Receptor (EGFR) tyrosine phosphorylation in cancer cells. Unlike ligand-dependent activation, the mechanism of this induction relies on the generation of hydrogen peroxide, which is involved in the activation of the catalytic site of the receptor and the inactivation of protein tyrosine phosphatase PTP-1B.

A simple purification procedure of D-amino-acid oxidase from Candida guilliermondii H(see symbol)-4.

D-amino-acid oxidase (EC 1.4.3.

Natural organic UV-absorbent coatings based on cellulose and lignin: designed effects on spectroscopic properties.

Novel nanocomposite coatings composed of cellulose nanocrystals (CNCs) and lignin (either synthetic or fractionated from spruce and corn stalks) were prepared without chemical modification or functionalization (via covalent attachment) of one of the two biopolymers. The spectroscopic properties of these coatings were investigated by UV-visible spectrophotometry and spectroscopic ellipsometry. When using the appropriate weight ratio of CNC/lignin (R), these nanocomposite systems exhibited high-performance optical properties, high transmittance in the visible spectrum, and high blocking in the UV spectrum.

Isolation, purification, and characterization of phenylpyruvate transaminating enzymes of Erwinia carotovora.

Enzymes of Erwinia carotovora that transaminate phenylpyruvate were isolated, purified, and characterized. Two aromatic aminotransferases (PAT1 and PAT2) and an aspartic aminotransferase (PAT3) were found. According to gel filtration, these enzymes have molecular weights of 76, 75, and 78 kDa.

Structure and optical properties of plant cell wall bio-inspired materials: cellulose-lignin multilayer nanocomposites.

Interfacial affinity between lignin model compound (dehydrogenation polymer [DHP]) and cellulose nanocristals (CN) was studied before building a nanocomposite cellulose/lignin in multilayer form by spin-coating method. The adsorption isotherm of DHP was measured by ellipsometry at the liquid/CN film interface and showed that the surface concentration of adsorbed DHP increases with the bulk concentration in solution. The DHP appeared as globular structures on cellulosic film, as observed by AFM.

The novel inhibitors of serine proteases.

Thirty optically active nonprotein alpha-amino acids and peptides based thereon have been screened for their ability to interact with bovine trypsin and proteinase K from Tritirachium album Limber, which belong to the group of serine proteases. Both structure-based drug design approach and determination of enzyme activity have been used to identify low molecular weight inhibitors of trypsin and proteinase K. Compounds have been selected that according to the docking analysis were able to interact with trypsin and proteinase K.

alpha,beta-Dehydrophenylalanine choline esters, a new class of reversible inhibitors of human acetylcholinesterase and butyrylcholinesterase.

Our goal was to design, synthesize, and evaluate new cholinesterase inhibitors. Fourteen dehydroamino acids esterified to choline and to its ternary analog were synthesized by a new method that gave a yield of 84-93%. The potency of the amino acid ester derivatives was tested by measuring K(i) values for inhibition of human red cell acetylcholinesterase and human plasma butyrylcholinesterase.

An unprecedented surface oxidation of polystyrene substrates by wet chemistry under basic conditions.

The surface of polystyrene substrates has been modified by wet chemistry consisting of a treatment with sodium hydroxide in a water-methanol solution at 50 degrees C for 15 h, under air atmosphere. The resulting samples were analyzed by XPS and AFM. The surface functional groups (hydroxyl and carboxyl functions) were assayed by radiolabeling.

beta-casein and symmetrical triblock copolymer (PEO-PPO-PEO and PPO-PEO-PPO) surface properties at the air-water interface.

A comparison of beta-casein and symmetrical triblock copolymer (PEO-PPO-PEO and PPO-PEO-PPO) adsorption layer properties at the air-water interface has been carried out by bubble tensiometry and ellipsometry. It has been verified that the equation of state parameters (pi approximately gamma(y)) obtained from surface pressure (pi) and ellipticity in Brewster conditions (rhoB), which is proportional to the surface concentration (gamma) data, are the same as those obtained from dilational modulus epsilon and pi data. These two consistent approaches give further support to the theoretical model of block copolymers which has been previously developed for protein adsorption at fluid interfaces.

Isolation, purification and physicochemical characterization of water-soluble Bacillus thuringiensis melanin.

Melanins are widely used in medicine, pharmacology, cosmetics and other fields. Although several technologies for the purification of water-insoluble dioxyphenylalanine (DOPA) melanins have been described, a source of water-soluble melanin is highly desirable. Here we describe an effective procedure for the isolation and purification of water-soluble melanin using the culture medium of Bacillus thuringiensis subsp.