Structure-guided mining of stereoselective reductive aminases for biocatalytic stereodivergent synthesis of chiral piperidinamine and derivatives.

Chiral azacyclic amine derivatives occupy a vital role of nitrogen-containing compounds, due to serve as foundational motifs in numerous pharmaceuticals and bioactive substances. Novel complementary enantioselective reductive aminases IRED9 and IRED11 were unveiled through comprehensive gene mining from Streptomyces viridochromogenes and Micromonospora echinaurantiaca, respectively, which both demonstrated enantiomeric excess (ee) values and conversion ratios of up to 99 % towards N-Boc-3-pyridinone (NBPO) and cyclopropylamine. IRED9 exhibited the highest activity at pH 8.

Repair of Osteochondral Defect with Acellular Cartilage Matrix and Thermosensitive Hydrogel Scaffold.

In the present study, acellular cartilage matrix (ACM) was modified with poly-l-lysine/hyaluronic acid (PLL/HA) multilayers via detergent-enzyme chemical digestion and layer-by-layer self-assembly technology. This modified ACM was then loaded with Transforming Growth Factor Beta 3 (TGF-β3) and incorporated into a thermosensitive hydrogel (TH) to create a HA/PLL-ACM/TH composite scaffold with sustained-release function. This study aimed to evaluate the efficacy of this novel composite scaffold in promoting chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and facilitating osteochondral defect repair.

Enhanced stereodivergent evolution of carboxylesterase for efficient kinetic resolution of near-symmetric esters through machine learning.

Carboxylesterases serve as potent biocatalysts in the enantioselective synthesis of chiral carboxylic acids and esters. However, naturally occurring carboxylesterases exhibit limited enantioselectivity, particularly toward ethyl 3-cyclohexene-1-carboxylate (CHCE, S1), due to its nearly symmetric structure. While machine learning effectively expedites directed evolution, the lack of models for predicting the enantioselectivity for carboxylesterases has hindered progress, primarily due to challenges in obtaining high-quality training datasets.

Biocatalytic Stereoselective Synthesis of Chiral Precursors for Liposoluble β Receptor Blocker Nebivolol.

Asymmetric reduction of 2-chloro-1-(6-fluorochroman-2-yl)ethan-1-one (NEB-7) into 2-chloro-1-(6-fluorochroman-2-yl)ethan-1-ol (NEB-8) is the crucial step for synthesis of liposoluble β receptor blocker nebivolol. Four efficient and stereoselective alcohol dehydrogenases were identified, enabling the stereoselective synthesis of all enantiomers of NEB-8 at a substrate loading of 137 g·L with ee values of >99% and high space-time yields. This study provides novel biocatalysts for the efficient synthesis of nebivolol precursors and uncovers the molecular basis for enantioselectivity manipulation by parametrization of Prelog's rule.

Classification and functional origins of stereocomplementary alcohol dehydrogenases for asymmetric synthesis of chiral secondary alcohols: A review.

Alcohol dehydrogenases (ADHs) mediated biocatalytic asymmetric reduction of ketones have been widely applied in the synthesis of optically active secondary alcohols with highly reactive hydroxyl groups ligated to the stereogenic carbon and divided into (R)- and (S)-configurations. Stereocomplementary ADHs could be applied in the synthesis of both enantiomers and are increasingly accepted as the "first of choice" in green chemistry due to the high atomic economy, low environmental factor, 100 % theoretical yield, and high environmentally friendliness. Due to the equal importance of complementary alcohols, development of stereocomplementary ADHs draws increasing attention.

Engineering Glucosamine-6-Phosphate Synthase to Achieve Efficient One-Step Biosynthesis of Glucosamine.

As an important functional monosaccharide, glucosamine (GlcN) is widely used in fields such as medicine, food nutrition, and health care. Here, we report a distinct GlcN biosynthesis method that utilizes engineered glucosamine-6-phosphate synthase (GlmS) to convert D-fructose to directly generate GlcN. The best variant obtained by using a combinatorial active-site saturation test/iterative saturation mutagenesis (CAST/ISM) strategy was a quadruple mutant S596D/V597G/S347H/G299Q (GlmS-BK19), which has a catalytic activity 1736-fold that of the wild type toward D-fructose.

Photocatalytic regeneration of nicotinamide cofactor biomimetics drives biocatalytic reduction by Old Yellow enzymes.

A key approach in developing green chemistry involves converting solar energy into chemical energy of biomolecules through photocatalysis. Photocatalysis can facilitate the regeneration of nicotinamide cofactors during redox processes. Nicotinamide cofactor biomimetics (NCBs) are economical substitutes for natural cofactors.

Semirational Design Strategy To Enhance the Thermostability and Catalytic Activity of Cytochrome P450 105D7 for the Degradation of the Pharmaceutically Active Compounds: Diclofenac.

Pharmaceutically active compounds are an important category of emerging pollutants, and their biological transformation processes in the environment are crucial for understanding and evaluating the migration, transformation, and environmental fate of emerging pollutants. The cytochrome P450 105 enzyme family has been proven to play an important role in the degradation of exogenous environmental pollutants. However, its thermostability and catalytic activity still need to be improved to better adapt to complex environmental conditions.

Structure-Guided Evolution of Cyclohexanone Monooxygenase Toward Bulky Omeprazole Sulfide: Substrate Migration and Stereoselectivity Inversion.

Structure-guided engineering of a CHMO from Amycolatopsis methanolica (AmCHMO) was performed for asymmetric sulfoxidation activity and stereoselectivity toward omeprazole sulfide. Initially, combinatorial active-site saturation test (CASTing) and iteratively saturation mutagenesis (ISM) were performed on 5 residues at the "bottleneck" of substrate tunnel, and MT3 was successfully obtained with a specific activity of 46.19 U/g and R-stereoselectivity of 99 % toward OPS.

Engineering diaryl alcohol dehydrogenase KpADH reveals importance of retaining hydration shell in organic solvent tolerance.

Alcohol dehydrogenases (ADHs) are synthetically important biocatalysts for the asymmetric synthesis of chiral alcohols. The catalytic performance of ADHs in the presence of organic solvents is often important since most prochiral ketones are highly hydrophobic. Here, the organic solvent tolerance of KpADH from Kluyveromyces polyspora was semi-rationally evolved.

Mining and tailor-made engineering of a novel keto reductase for asymmetric synthesis of structurally hindered γ- and δ-lactones.

A novel carbonyl reductase from Hyphopichia burtoni (HbKR) was discovered by gene mining. HbKR is a NADPH-dependent dual function enzyme with reduction and oxidation activity belonging to SDR superfamily. HbKR strictly follows Prelog priority in the reduction of long-chain aliphatic keto acids/esters containing remote carbonyl groups, such as 4-oxodecanoic acid and 5-oxodecanoic acid, producing (S)-γ-decalactone and (S)-δ-decalactone in >99 % e.

Pannexin 3 activates P2X7 receptor to mediate inflammation and cartilage matrix degradation in temporomandibular joint osteoarthritis.

Pannexin 3 (Panx3) is involved in regulation of the proliferation and differentiation in chondrocytes and pathological process in osteoarthritis, but its role and potential mechanism in temporomandibular joint osteoarthritis (TMJOA) are still unclear, which are thus explored in our research. We established TMJOA animal model and cell model. In vivo, after silencing Panx3, the pathological changes of condylar cartilage tissue were analyzed by tissue staining, while expressions of Panx3, P2X7 receptor (P2X7R), NLRP3, and cartilage matrix-related genes were measured by immunohistochemistry (for animal model) or immunofluorescence (for cell model), quantitative reverse-transcription polymerase chain reaction (qRT-PCR) or western blot.

Efficient production of hyaluronic acid by Streptococcus zooepidemicus using two-stage semi-continuous fermentation.

Hyaluronic acid is a kind of mucopolysaccharide that has wide applications in cosmetics, health food, and orthopedics. Using Streptococcus zooepidemicus ATCC 39920 as parent, a beneficial mutant SZ07 was obtained by UV mutagenesis, giving 1.42 g/L hyaluronic acid in shake flasks.

Fibroblast growth factor 9 reduces TBHP-induced oxidative stress in chondrocytes and diminishes mouse osteoarthritis by activating ERK/Nrf2 signaling pathway.

Osteoarthritis (OA) is a degenerative and progressive disease that affects joints. Pathologically, it is characterized by oxidative stress-mediated excessive chondrocyte apoptosis and mitochondrial dysfunction. Fibroblast growth factor 9 (FGF9) has been shown to exert antioxidant effects and prevent degenerative diseases by activating ERK-related signaling pathways.

Engineering the Thermostability of a d-Carbamoylase Based on Ancestral Sequence Reconstruction for the Efficient Synthesis of d-Tryptophan.

Employing ancestral sequence reconstruction and consensus sequence analysis, the thermostability of a novel d-carbamoylase derived from (HyuC) was engineered through greedy-oriented iterative combinatorial mutagenesis. A mutant S202P/E208D/R277L (M4Th3) was obtained with significantly elevated thermostability. M4Th3 has a half-life of 36.

Self-Sufficient In Vitro Multi-Enzyme Cascade for Efficient Synthesis of Danshensu from l-DOPA.

Danshensu (DSS), a traditional Chinese medicine, is widely used for the treatment of cardiovascular and cancer diseases. Here, a one-pot multi-enzyme cascade pathway was designed for DSS synthesis from l-DOPA using tyrosine aminotransferase from (TyrB) and d-isomer-specific 2-hydroxyacid dehydrogenase from (D2-HDH). Glutamate dehydrogenase from (gluD) was also introduced for a self-sufficient system of α-ketoglutaric acid and NADH.

Engineering of a Baeyer-Villiger monooxygenase reveals key residues for the asymmetric oxidation of omeprazole sulfide.

The structure-guided engineering of a BVMO from (BVMO) was performed for its asymmetric sulfoxidation activity toward omeprazole sulfide. Based on the structural model of BVMO, key residues that line the substrate entrance tunnel and the binding pocket were identified, and variants were interrogated with sulfides of varied sizes. The best mutant MT2 (F442A/R337P) was obtained with a specific activity of 2.

Directed reconstruction of a novel ancestral alcohol dehydrogenase featuring shifted pH-profile, enhanced thermostability and expanded substrate spectrum.

Ancestral enzymes are promising for industrial biotechnology due to high stability and catalytic promiscuity. An effective protocol was developed for the directed resurrection of ancestral enzymes. Employing genome mining with diaryl alcohol dehydrogenase KpADH as the probe, descendant enzymes D10 and D11 were firstly identified.

Development, Characterization and Osteoinductive Efficacy of a Novel Biomimetically-Precipitated Nanocrystalline Calcium Phosphate With Internally-Incorporated Bone Morphogenetic Protein-2.

The repair of large-volume bone defects (LVBDs) remains a great challenge in the fields of orthopedics and maxillofacial surgery. Most clinically available bone-defect-filling materials lack proper degradability and efficient osteoinductivity. In this study, we synthesized a novel biomimetically-precipitated nanocrystalline calcium phosphate (BpNcCaP) with internally incorporated bone morphogenetic protein-2 (BpNcCaP + BMP-2) with an aim to develop properly degradable and highly osteoinductive granules to repair LVBDs.

Application Effect of the 6S Care Model in Sterilization in the Department of Stomatology and Its Impact on the Incidence of Nosocomial Infection.

Objective: The study aimed to explore the effectiveness of the 6S care model in sterilization in department of stomatology and its impact on the incidence of nosocomial infections.

Methods: The infection surveillance indicators of the department of stomatology implementing the routine sterilization care model in 2019 were selected as the general group (including 140 patients and 140 cases of oral instrument kits for unpacking), and the infection surveillance indicators of the department of stomatology implementing the 6S care model in 2020 were selected as the 6S group (including 140 patients and 140 cases of oral instrument kits for unpacking). Analysis of the air culture qualification rate of the consultation room + operating room, medical equipment sterilization qualification rate, medical equipment damage rate, incidence of nosocomial infections, satisfaction of medical and nursing staff with instrument sterilization, and patient satisfaction with medical and nursing staff care services under different care models was carried out.

Zoledronate promotes ECM degradation and apoptosis via Wnt/β-catenin.

This study examined the potential mechanism of zoledronate on interleukin (IL)-1β-induced temporomandibular joint osteoarthritis (TMJOA) chondrocytes, using IL-1β-induced rabbit immortalized mandibular condylar chondrocytes cultured with zoledronate. Cell viability, apoptosis, mRNA, and protein expression of relevant genes involved in extracellular matrix (ECM) degradation, apoptosis, and Wnt/β-catenin signaling were examined. The involvement of the Wnt/β-catenin signaling was examined using Wnt/β-catenin inhibitor (2-(4-(trifluoromethyl)phenyl)-7,8-dihydro-5H-thiopyrano[4,3-d]pyrimidin-4-ol (XAV-939)) and activator lithium chloride (LiCl).

Hydrogen Abstraction by Alkoxyl Radicals: Computational Studies of Thermodynamic and Polarity Effects on Reactivities and Selectivities.

Density functional theory calculations (ωB97X-D) are reported for the reactions of methoxy, -butoxy, trichloroethoxy, and trifluoroethoxy radicals with a series of 26 C-H bonds in different environments characteristic of a variety of hydrocarbons and substituted derivatives. The variations in activation barriers are analyzed with modified Evans-Polanyi treatments to account for polarity and unsaturation effects. The treatments by Roberts and Steel and by Mayer have inspired the development of a simple treatment involving the thermodynamics of reactions, the difference between the reactant radical and product radical electronegativities, and the absence or presence of α-unsaturation.

Systematic review and meta-analysis: influence of iron deficiency anemia on blood glycosylated hemoglobin in diabetic patients.

Background: Diabetes is a common metabolic disease with an increasing incidence in middle-aged and elderly people in recent years. Chronic hyperglycemia is the basic feature of diabetes, which can cause long-term damage to eyes, kidneys, nerves, heart, and blood vessels, resulting in functional decline or even failure. Glycosylated hemoglobin (HbA1c) can be used as an indicator of an individual's blood sugar status over the past 3 months; however, it is slightly affected by ischemic anemia.

Relationship between the absolute lymphocyte count/absolute monocyte count ratio, soluble interleukin 2 receptor level, serum programmed cell death 1 level, and the prognosis of patients with diffuse large B-cell lymphoma.

Background: To analyze the relationship between the peripheral blood absolute lymphocyte count (ALC)/absolute monocyte count (AMC) ratio, soluble interleukin 2 receptor (sIL-2R) level, serum programmed cell death 1 (PD-1) level, and the prognosis of patients with diffuse large B-cell lymphoma (DLBCL).

Methods: A total of 78 patients with DLBCL admitted to hospital and 30 healthy controls were enrolled as the case group and control group between August 2019 and June 2020, respectively. The ALC/AMC ratio and the levels of sIL-2R and serum PD-1 between the 2 groups and among patients with different prognoses were compared.

Sustainable one-pot chemo-enzymatic synthesis of chiral furan amino acid from biomass via magnetic solid acid and threonine aldolase.

Sustainable synthesis of valuable noncanonical amino acids from renewable feedstocks is of great importance. Here, a feasible chemo-enzymatic procedure was developed for the synthesis of chiral β-(2-furyl)serine from biomass catalyzed by a solid acid catalyst and immobilized E. coli whole-cell harboring l-threonine aldolase.