Selective microbial production of lacto-N-fucopentaose I in Escherichia coli using engineered α-1,2-fucosyltransferases.

Lacto-N-fucopentaose I (LNFP I) is the second most abundant fucosylated human milk oligosaccharide (HMO) in breast milk after 2'-fucosyllactose (2'-FL). Studies have reported that LNFP I exhibits antimicrobial activity against group B Streptococcus and antiviral effects against Enterovirus and Norovirus. Microbial production of HMOs by engineered Escherichia coli is an attractive, low-cost process, but few studies have investigated production of long-chain HMOs, including the pentasaccharide LNFP I.

AsiteDesign: a Semirational Algorithm for an Automated Enzyme Design.

With advances in protein structure predictions, the number of available high-quality structures has increased dramatically. In light of these advances, structure-based enzyme engineering is expected to become increasingly important for optimizing biocatalysts for industrial processes. Here, we present AsiteDesign, a Monte Carlo-based protocol for structure-based engineering of active sites.

A Plurizyme with Transaminase and Hydrolase Activity Catalyzes Cascade Reactions.

Engineering dual-function single polypeptide catalysts with two abiotic or biotic catalytic entities (or combinations of both) supporting cascade reactions is becoming an important area of enzyme engineering and catalysis. Herein we present the development of a PluriZyme, TR E , with efficient native transaminase (k : 69.49±1.

Impact of SARS-CoV-2 (COVID-19) pandemic on patients with lysosomal storage disorders and restoration of services: experience from a specialist centre.

This study aims to evaluate the impact of the COVID-19 pandemic on the lysosomal disorders unit (LSDU) at Royal Free London NHS Foundation Trust (RFL), a highly specialised national service for diagnosis and management of adults with lysosomal storage disorders (LSD). Review of home care enzyme replacement therapy (ERT) and emergency care, and COVID-19 shielding categories as per UK government guidance. New clinical pathways were developed to manage patients safely during the pandemic; staff well-being initiatives are described.

Structural-Based Modeling in Protein Engineering. A Must Do.

Biotechnological solutions will be a key aspect in our immediate future society, where optimized enzymatic processes through enzyme engineering might be an important solution for waste transformation, clean energy production, biodegradable materials, and green chemistry, for example. Here we advocate the importance of structural-based bioinformatics and molecular modeling tools in such developments. We summarize our recent experiences indicating a great prediction/success ratio, and we suggest that an early phase should be performed in enzyme engineering studies.

Transoral Laser-Assisted Total Laryngectomy: Expanding the TLM's World.

Introduction: The introduction of laryngeal transoral procedures has created a shift in the treatment of laryngeal cancers towards the primary surgical management of patients. In this study, we aimed to evaluate the safety, efficacy, and feasibility of the transoral laser-assisted total laryngectomy (TLM-TL) in advanced laryngeal cancer. .

Mechanism of Biocatalytic Friedel-Crafts Acylation by Acyltransferase from .

Acyltransferases isolated from (ATase) and (ATase) have recently been reported to catalyze the Friedel-Crafts acylation, providing a biological version of this classical organic reaction. These enzymes catalyze the cofactor-independent acylation of monoacetylphloroglucinol (MAPG) to diacetylphloroglucinol (DAPG) and phloroglucinol (PG) and have been demonstrated to have a wide substrate scope, making them valuable for potential applications in biocatalysis. Herein, we present a detailed reaction mechanism of ATase on the basis of quantum chemical calculations, employing a large model of the active site.

Origins of Enantiopreference of Mycobacterium smegmatis Acyl Transferase: A Computational Analysis.

Acyl transferase from Mycobacterium smegmatis (MsAcT) is a promising biocatalyst because it catalyzes an acyl transfer reaction in aqueous solution, thereby accepting many primary and secondary alcohols as substrates. MsAcT also exhibits high enantioselectivity for a selected number of secondary alcohols. To increase the applicability of this enzyme for the production of optically active compounds, a detailed understanding of the reaction mechanism and the factors that affect enantioselectivity is essential.

Mechanistic alternatives for peptide bond formation on the ribosome.

The peptidyl transfer reaction on the large ribosomal subunit depends on the protonation state of the amine nucleophile and exhibits a large kinetic solvent isotope effect (KSIE ∼8). In contrast, the related peptidyl-tRNA hydrolysis reaction involved in termination shows a KSIE of ∼4 and a pH-rate profile indicative of base catalysis. It is, however, unclear why these reactions should proceed with different mechanisms, as the experimental data suggests.

Catalytic Adaptation of Psychrophilic Elastase.

The class I pancreatic elastase from Atlantic salmon is considered to be a cold-adapted enzyme in view of the cold habitat, the reduced thermostability of the enzyme, and the fact that it is faster than its mesophilic porcine counterpart at room temperature. However, no experimental characterization of its catalytic properties at lower temperatures has actually been reported. Here we use extensive computer simulations of its catalytic reaction, at different temperatures and with different peptide substrates, to compare its characteristics with those of porcine pancreatic elastase, with which it shares 67% sequence identity.

A New Approach to Survival Analysis of Head and Neck Squamous Cell Carcinoma.

Background: Squamous cell carcinoma is the most common histological subtype of head and neck cancers.

Methods: In a retrospective longitudinal study, we assessed the risk of local or metastatic recurrence and death in 140 patients with head and neck squamous cell carcinoma (HNSCC). Multivariate and shared frailty models were used for survival analysis with sex, primary tumor site, grade and stage of the tumor, and treatment modalities as contributing factors.

Entropy and Enzyme Catalysis.

The role played by entropy for the enormous rate enhancement achieved by enzymes has been debated for many decades. There are, for example, several confirmed cases where the activation free energy is reduced by around 10 kcal/mol due to entropic effects, corresponding to a rate enhancement of ∼10 compared to the uncatalyzed reaction. However, despite substantial efforts from both the experimental and theoretical side, no real consensus has been reached regarding the origin of such large entropic contributions to enzyme catalysis.

Enzyme catalysis by entropy without Circe effect.

Entropic effects have often been invoked to explain the extraordinary catalytic power of enzymes. In particular, the hypothesis that enzymes can use part of the substrate-binding free energy to reduce the entropic penalty associated with the subsequent chemical transformation has been very influential. The enzymatic reaction of cytidine deaminase appears to be a distinct example.

Origin of the Enigmatic Stepwise Tight-Binding Inhibition of Cyclooxygenase-1.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used for the treatment of pain, fever, inflammation, and some types of cancers. Their mechanism of action is the inhibition of isoforms 1 and 2 of the enzyme cyclooxygenase (COX-1 and COX-2, respectively). However, both nonselective and selective NSAIDs may have side effects that include gastric intestinal bleeding, peptic ulcer formation, kidney problems, and occurrences of myocardial infarction.

Chemical reaction mechanisms in solution from brute force computational Arrhenius plots.

Decomposition of activation free energies of chemical reactions, into enthalpic and entropic components, can provide invaluable signatures of mechanistic pathways both in solution and in enzymes. Owing to the large number of degrees of freedom involved in such condensed-phase reactions, the extensive configurational sampling needed for reliable entropy estimates is still beyond the scope of quantum chemical calculations. Here we show, for the hydrolytic deamination of cytidine and dihydrocytidine in water, how direct computer simulations of the temperature dependence of free energy profiles can be used to extract very accurate thermodynamic activation parameters.

Antimalarial Effects of Iranian Flora Artemisia sieberi on Plasmodium berghei In Vivo in Mice and Phytochemistry Analysis of Its Herbal Extracts.

The aim of this study is pharmacochemistry of Iranian flora Artemisia sieberi and its antimalarial effects on Plasmodium berghei in vivo. This is the first application of A. sieberi for treatment of murine malaria.

The relationship between Helicobacter pylori infection and gastric adenocarcinoma in Northern Iran.

Colonization of the human stomach with Helicobacter pylori induces chronic gastritis and is associated with the development of gastric and duodenal ulcers, gastric carcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Infection with an H. pylori strain containing the cytotoxin-associated (cagA) gene (a marker for a pathogenicity island) may increase the risk of atrophic gastritis and gastric cancer.

Composition and antimicrobial activity of the essential oil of Artemisia kulbadica from Iran.

The hydrodistilled volatile oil from the aerial parts of Artemisia kulbadica Boiss. & Buhse was investigated by a combination of GC and GC/MS. Twenty-seven compounds were identified, representing 92.