The three-dimensional structure of DapE from Enterococcus faecium reveals new insights into DapE/ArgE subfamily ligand specificity.

DapE is a Zn-metallohydrolase recognized as a drug target for bacterial control. It is a homodimer that requires the exchange of interface strands by an induced fit essential for catalysis. Identifying novel anti-DapE agents requires greater structural details.

Structural and functional properties of uridine 5'-monophosphate synthase from Coffea arabica.

In higher eukaryotes and plants, the last two sequential steps in the de novo biosynthesis of uridine 5'-monophosphate (UMP) are catalyzed by a bifunctional natural chimeric protein called UMP synthase (UMPS). In higher plants, UMPS consists of two naturally fused enzymes: orotate phosphoribosyltransferase (OPRTase) at N-terminal and orotidine-5'-monophosphate decarboxylase (ODCase) at C-terminal. In this work, we obtained the full functional recombinant protein UMPS from Coffea arabica (CaUMPS) and studied its structure-function relationships.

Interaction of N-succinyl-diaminopimelate desuccinylase with flavonoids.

DapE is an enzyme that belongs to the meso-diaminopimelate/Lysine pathway. It is recognized as an antimicrobial target, hence compounds that inhibit its catalytic activity are required. The principal features considered in the selection of potential inhibitors for this enzyme are compounds containing metal binding groups that could block access of the substrate to the Zinc metal centers and/or block the assembly of the oxyanion hole.

Psychological distress and lack of PINK1 promote bioenergetics alterations in peripheral blood mononuclear cells.

Psychological distress induces oxidative stress and alters mitochondrial metabolism in the nervous and immune systems. Psychological distress promotes alterations in brain metabolism and neurochemistry in wild-type (WT) rats in a similar manner as in Parkinsonian rats lacking endogenous PTEN-induced kinase 1 (PINK1), a serine/threonine kinase mutated in a recessive forms of Parkinson's disease. PINK1 has been extensively studied in the brain, but its physiological role in peripheral tissues and the extent to which it intersects with the neuroimmune axis is not clear.

FDA-approved thiol-reacting drugs that potentially bind into the SARS-CoV-2 main protease, essential for viral replication.

Emergent novel SARS-CoV-2 is responsible for the current pandemic outbreak of severe acute respiratory syndrome with high mortality among the symptomatic population worldwide. Given the absence of a current vaccine or specific antiviral treatment, it is urgent to search for FDA-approved drugs that can potentially inhibit essential viral enzymes. The inhibition of 3CL has potential medical application, due to the fact that it is required for processing of the first translated replicase polyproteins into a series of native proteins, which are essential for viral replication in the host cell.

Development of an Innovative Nonanimal Training Model for Infant Pleural Effusion Drainage via Pigtail Catheter Placement.

Background: Chest tube placement is an important skill for providers and bedside nurses caring for critically ill infants, allowing for the evacuation of pleural fluid and pneumothoraces. No realistic simulation models are commercially available for trainees to practice and learn this skill on infants.

Purpose: Our objective was to develop an inexpensive and reproducible model for percutaneous pleural pigtail placement for pleural fluid removal via the Seldinger technique.

Proanthocyanidins with a Low Degree of Polymerization are Good Inhibitors of Digestive Enzymes Because of their Ability to form Specific Interactions: A Hypothesis.

Inhibition of target digestive enzymes is an accepted strategy to prevent diseases such as obesity and diabetes. Proanthocyanidins (PACs) are known for their ability to bind, inhibit, and precipitate enzymes, which makes them potential bioDrugs with an impact on the digestive process. PAC degree of polymerization (DP) is one of the structural features responsible for their differential inhibitory potency but the explanation for this phenomenon is still unclear.

Blood mononuclear cells as speculum of emotional stress analyzed by synchrotron infrared spectroscopy and a nootropic drug.

Chronic psychological stress is an important public health issue which generates behavioral changes, anxiety, immunosuppression and oxidative damage. Piracetam is a cognitive enhancer, at cellular level it protects from oxidative stress. The aim of this study was to evaluate the effect of psychological stress and of piracetam on circulating mononuclear cells by analyzing the biochemical spectrome using Synchrotron Radiation Fourier Transform Infrared Microspectroscopy (SR-μFTIR).

Inhibition of Pancreatic Lipase by Polyphenols: A Kinetic, Fluorescence Spectroscopy and Molecular Docking Study.

The inhibitory activity and binding characteristics of caffeic acid, -coumaric acid, quercetin and capsaicin, four phenolic compounds found in hot pepper, against porcine pancreatic lipase activity were studied and compared to hot pepper extract. Quercetin was the strongest inhibitor (IC=(6.1±2.

Chlorpromazine and dimethyl sulfoxide modulate the catalytic activity of the plasma membrane Ca-ATPase from human erythrocyte.

The plasma membrane Ca-ATPase (PMCA) removes Ca from the cytosol into the extracellular space. Its catalytic activity can be stimulated by calmodulin (CaM) or by limited proteolysis. We evaluated the effect of chlorpromazine (CPZ) and dimethyl sulfoxide (DMSO) over the hydrolytic activity of PMCA.

Polyphenolic Compounds and Digestive Enzymes: In Vitro Non-Covalent Interactions.

The digestive enzymes-polyphenolic compounds (PCs) interactions behind the inhibition of these enzymes have not been completely studied. The existing studies have mainly analyzed polyphenolic extracts and reported inhibition percentages of catalytic activities determined by UV-Vis spectroscopy techniques. Recently, pure PCs and new methods such as isothermal titration calorimetry and circular dichroism have been applied to describe these interactions.

Inhibition of Urease by Disulfiram, an FDA-Approved Thiol Reagent Used in Humans.

Urease is a nickel-dependent amidohydrolase that catalyses the decomposition of urea into carbamate and ammonia, a reaction that constitutes an important source of nitrogen for bacteria, fungi and plants. It is recognized as a potential antimicrobial target with an impact on medicine, agriculture, and the environment. The list of possible urease inhibitors is continuously increasing, with a special interest in those that interact with and block the flexible active site flap.

Novel Redox-Dependent Esterase Activity (EC 3.1.1.2) for DJ-1: Implications for Parkinson's Disease.

Mutations the in human DJ-1 (hDJ-1) gene are associated with early-onset autosomal recessive forms of Parkinson's disease (PD). hDJ-1/parkinsonism associated deglycase (PARK7) is a cytoprotective multi-functional protein that contains a conserved cysteine-protease domain. Given that cysteine-proteases can act on both amide and ester substrates, we surmised that hDJ-1 possessed cysteine-mediated esterase activity.

Investigations of Sulfur Chemical Status with Synchrotron Micro Focused X-ray fluorescence and X-ray Absorption Spectroscopy.

Sulfur (S) is an essential macronutrient for all living organisms. A variety of organic and inorganic S species with oxidation states ranging from -2 to +6 exist. Today few spectroscopic and biochemical methods are used to investigate sulfur oxidation state and reactivity in biological samples.

Comparative study of two GH19 chitinase-like proteins from Hevea brasiliensis, one exhibiting a novel carbohydrate-binding domain.

Plants express chitinase and chitinase-like proteins (CLPs) belonging to the glycosyl hydrolases of the GH18 and GH19 families, which exhibit varied functions. CLPs in the GH18 family have been structurally and functionally characterized; however, there are no structures available for any member of the GH19 family. In this study, two CLPs of the GH19 family from the rubber tree Hevea brasiliensis (HbCLP1 and HbCLP2) were cloned, expressed and characterized.

Potential monovalent cation-binding sites in aldehyde dehydrogenases.

Potassium ions are non-essential activators of several aldehyde dehydrogenases (ALDHs), whereas a few others require the cation for activity. Two kinds of cation-binding sites, which we named intra-subunit and inter-subunit, have been observed in crystal structures of ALDHs, and based on reported crystallographic data, we here propose the existence of a third kind located in the central cavity of some tetrameric ALDHs. Given the high structural similarity between these enzymes, cation-binding sites may be present in many other members of this superfamily.

Structural determinants of substrate specificity in aldehyde dehydrogenases.

Within the aldehyde dehydrogenase (ALDH) superfamily, proteins belonging to the ALDH9, ALDH10, ALDH25, ALDH26 and ALDH27 families display activity as ω-aminoaldehyde dehydrogenases (AMADHs). These enzymes participate in polyamine, choline and arginine catabolism, as well as in synthesis of several osmoprotectants and carnitine. Active site aromatic and acidic residues are involved in binding the ω-aminoaldehydes in plant ALDH10 enzymes.

Amino acid residues critical for the specificity for betaine aldehyde of the plant ALDH10 isoenzyme involved in the synthesis of glycine betaine.

Plant Aldehyde Dehydrogenase10 (ALDH10) enzymes catalyze the oxidation of ω-primary or ω-quaternary aminoaldehydes, but, intriguingly, only some of them, such as the spinach (Spinacia oleracea) betaine aldehyde dehydrogenase (SoBADH), efficiently oxidize betaine aldehyde (BAL) forming the osmoprotectant glycine betaine (GB), which confers tolerance to osmotic stress. The crystal structure of SoBADH reported here shows tyrosine (Tyr)-160, tryptophan (Trp)-167, Trp-285, and Trp-456 in an arrangement suitable for cation-π interactions with the trimethylammonium group of BAL. Mutation of these residues to alanine (Ala) resulted in significant K(m)(BAL) increases and V(max)/K(m)(BAL) decreases, particularly in the Y160A mutant.

Novel NADPH-cysteine covalent adduct found in the active site of an aldehyde dehydrogenase.

PaBADH (Pseudomonas aeruginosa betaine aldehyde dehydrogenase) catalyses the irreversible NAD(P)+-dependent oxidation of betaine aldehyde to its corresponding acid, the osmoprotector glycine betaine. This reaction is involved in the catabolism of choline and in the response of this important pathogen to the osmotic and oxidative stresses prevalent in infection sites. The crystal structure of PaBADH in complex with NADPH showed a novel covalent adduct between the C2N of the pyridine ring and the sulfur atom of the catalytic cysteine residue, Cys286.

Crystallographic evidence for active-site dynamics in the hydrolytic aldehyde dehydrogenases. Implications for the deacylation step of the catalyzed reaction.

The overall chemical mechanism of the reaction catalyzed by the hydrolytic aldehyde dehydrogenases (ALDHs) involves three main steps: (1) nucleophilic attack of the thiol group of the catalytic cysteine on the carbonyl carbon of the aldehyde substrate; (2) hydride transfer from the tetrahedral thiohemiacetal intermediate to the pyridine ring of NAD(P)(+); and (3) hydrolysis of the resulting thioester intermediate (deacylation). Crystal structures of different ALDHs from several organisms-determined in the absence and presence of bound NAD(P)(+), NAD(P)H, aldehydes, or acid products-showed specific details at the atomic level about the catalytic residues involved in each of the catalytic steps. These structures also showed the conformational flexibility of the nicotinamide half of the cofactor, and of the catalytic cysteinyl and glutamyl residues, the latter being the general base that activates the hydrolytic water molecule in the deacylation step.

Kinetic and structural features of betaine aldehyde dehydrogenases: mechanistic and regulatory implications.

The betaine aldehyde dehydrogenases (BADH; EC 1.2.1.