Identification and structure-based engineering of a dipeptidase CpPepD from Clostridium perfringens for the synthesis of l-carnosine.

l-Carnosine (l-Car), an endogenous dipeptide presents in muscle and brain tissues of various vertebrates, has a wide range of application values. The enzymatic preparation of l-Car is a promising synthetic method because it avoids the protection and deprotection steps. In the present study, a dipeptidase gene (CpPepD) from Clostridium perfringens with high l-Car synthetic activity was cloned and characterized.

Progress in Understanding Oxidative Stress, Aging, and Aging-Related Diseases.

Under normal physiological conditions, reactive oxygen species (ROS) are produced through redox reactions as byproducts of respiratory and metabolic activities. However, due to various endogenous and exogenous factors, the body may produce excessive ROS, which leads to oxidative stress (OS). Numerous studies have shown that OS causes a variety of pathological changes in cells, including mitochondrial dysfunction, DNA damage, telomere shortening, lipid peroxidation, and protein oxidative modification, all of which can trigger apoptosis and senescence.

Reconstruction the feedback regulation of amino acid metabolism to develop a non-auxotrophic L-threonine producing Corynebacterium glutamicum.

L-Threonine is an important feed additive with the third largest market size among the amino acids produced by microbial fermentation. The GRAS (generally regarded as safe) industrial workhorse Corynebacterium glutamicum is an attractive chassis for L-threonine production. However, the present L-threonine production in C.

ECMpy 2.0: A Python package for automated construction and analysis of enzyme-constrained models.

Genome-scale metabolic models (GEMs) have been widely employed to predict microorganism behaviors. However, GEMs only consider stoichiometric constraints, leading to a linear increase in simulated growth and product yields as substrate uptake rates rise. This divergence from experimental measurements prompted the creation of enzyme-constrained models (ecModels) for various species, successfully enhancing chemical production.

Multivariate modular metabolic engineering and medium optimization for vitamin B production by .

Vitamin B is a complex compound synthesized by microorganisms. The industrial production of vitamin B relies on specific microbial fermentation processes. has been utilized as a host for the biosynthesis of vitamin B, incorporating approximately 30 heterologous genes.

Effects of dietary iron supplementation on reproductive performance of sows and growth performance of piglets.

This experiment aimed to investigate the effects of dietary iron supplementation from different sources on the reproductive performance of sows and the growth performance of piglets. A total of 87 sows with similar farrowing time were blocked by body weight at day 85 of gestation, and assigned to one of three dietary treatments (n = 29 per treatment): basal diet, basal diet supplemented with 0.2% ferrous sulfate (FeSO4), and basal diet supplemented with 0.

Quantitative measurement of cell-surface displayed proteins based on split-GFP assembly.

Background: Microbial cell surface display technology allows immobilizing proteins on the cell surface by fusing them to anchoring motifs, thereby endowing the cells with diverse functionalities. However, the assessment of successful protein display and the quantification of displayed proteins remain challenging. The green fluorescent protein (GFP) can be split into two non-fluorescent fragments, while they spontaneously assemble and emit fluorescence when brought together through complementation.

Engineering and finetuning expression of SerC for balanced metabolic flux in vitamin B production.

Vitamin B plays a crucial role in cellular metabolism and stress response, making it an essential component for growth in all known organisms. However, achieving efficient biosynthesis of vitamin B faces the challenge of maintaining a balanced distribution of metabolic flux between growth and production. In this study, our focus is on addressing this challenge through the engineering of phosphoserine aminotransferase (SerC) to resolve its redundancy and promiscuity.

Enhancing Poly-γ-glutamic Acid Production in BL01 through a Multienzyme Assembly Strategy and Expression Features of Glutamate Synthesis from .

The enhancement of intracellular glutamate synthesis in glutamate-independent poly-γ-glutamic acid (γ-PGA)-producing strains is an essential strategy for improving γ-PGA production. BL01ΔΔΔΔ-- for the efficient synthesis of γ-PGA was constructed through expression of glutamate synthesis features of , which increased the titer of γ-PGA by 2.18-fold (3.

[Advances in fermentative production of L-tryptophan: a review].

L-tryptophan is an essential amino acid that is widely used in food, medicine and feed sectors. L-tryptophan can be produced through fermentation, and the main producing strains are engineered and , which are constructed by rational design methods based on metabolic engineering and synthetic biology. However, due to the long metabolic pathway, complex and unclear regulatory mechanism for L-tryptophan production in microbial cells, the production efficiency and robustness of L-tryptophan producing strains are still low.

Computational mechanistic investigation of the kinetic resolution of α-methyl-phenylacetaldehyde by norcoclaurine synthase.

Norcoclaurine synthase from Thalictrum flavum (TfNCS) demonstrated high stereospecificity and yield in catalyzing the Pictet-Spengler reaction of dopamine with chiral aldehydes, achieving kinetic resolution of aldehydes. However, the mechanism and the factors contributing to the stereoselectivity remain unclear. Herein, by using quantum chemical calculations, the mechanisms of TfNCS-catalyzed reactions of dopamine with both enantiomers of α-methyl-phenylacetaldehyde are studied.

Tyrosinase-Modified UHMW SELP Polymers as Wet and Underwater Adhesives to Achieve Multi-interface Adhesion.

The presence of a hydration layer in humid and underwater environments challenges adhesive-substrate interactions and prevents effective bonding, which has become a significant obstacle to the development of adhesives in the industrial and biomedical fields. In this study, ultrahigh-molecular-weight (UHMW) silk-elastin-like proteins (SELP) with 3,4-dihydroxyphenylalanine (DOPA) converted from tyrosine residues by tyrosinase exhibited excellent adhesive properties on different interfaces, such as glass, aluminum, wood, polypropylene sheets, and pigskin, under both dry and wet conditions. Additionally, by incorporating trace amounts of cross-linking agents like Fe, NaIO, and tris(hydroxymethyl) phosphine (THP), the mussel-inspired adhesives maintained a stable and excellent adhesion, broadening the conditions of application.

Metabolic engineering of Escherichia coli for high-level production of the biodegradable polyester monomer 2-pyrone-4,6-dicarboxylic acid.

2-Pyrone-4,6-dicarboxylic acid (PDC), a chemically stable pseudo-aromatic dicarboxylic acid, is a promising building block compound for manufacturing biodegradable polyesters. This study aimed to construct high-performance cell factories enabling the efficient production of PDC from glucose. Firstly, the effective enzymes of the PDC biosynthetic pathway were overexpressed on the chromosome of the 3-dehydroshikimate overproducing strain.

Engineering the activity and thermostability of a carboxylic acid reductase in the conversion of vanillic acid to vanillin.

Vanillin is a valuable natural product that can be used as a fragrance and additive. Recent research in the biosynthesis of vanillin has brought attention to a key enzyme, carboxylic acid reductase (CAR), which catalyzes the reduction of vanillic acid to vanillin. Nevertheless, the biosynthesis of vanillin is hampered by the low activity and stability of CAR.

Omics data analysis reveals the system-level constraint on cellular amino acid composition.

Proteins play a pivotal role in coordinating the functions of organisms, essentially governing their traits, as the dynamic arrangement of diverse amino acids leads to a multitude of folded configurations within peptide chains. Despite dynamic changes in amino acid composition of an individual protein (referred to as AAP) and great variance in protein expression levels under different conditions, our study, utilizing transcriptomics data from four model organisms uncovers surprising stability in the overall amino acid composition of the total cellular proteins (referred to as AACell). Although this value may vary between different species, we observed no significant differences among distinct strains of the same species.

Engineering the Activity of a Newly Identified Arylalkylamine N-Acetyltransferase in the Acetylation of 5-Hydroxytryptamine.

Arylalkylamine N-acetyltransferase (AANAT) serves as a key enzyme in the biosynthesis of melatonin by transforming 5-hydroxytryptamine (5-HT) to N-acetyl-5-hydroxytryptamine (NAS), while its low activity may hinder melatonin yield. In this study, a novel AANAT derived from Sus scrofa (SsAANAT) was identified through data mining using 5-HT as a model substrate, and a rational design of SsAANAT was conducted in the quest to improving its activity. After four rounds of mutagenesis procedures, a triple combinatorial dominant mutant M3 was successfully obtained.

Mutagenesis techniques for evolutionary engineering of microbes - exploiting CRISPR-Cas, oligonucleotides, recombinases, and polymerases.

The natural process of evolutionary adaptation is often exploited as a powerful tool to obtain microbes with desirable traits. For industrial microbes, evolutionary engineering is often used to generate variants that show increased yields or resistance to stressful industrial environments, thus obtaining superior microbial cell factories. However, even in large populations, the natural supply of beneficial mutations is typically low, which implies that obtaining improved microbes is often time-consuming and inefficient.

Ginsenoside Rb1, Compound K and 20(S)-Protopanaxadiol Attenuate High-Fat Diet-Induced Hyperlipidemia in Rats via Modulation of Gut Microbiota and Bile Acid Metabolism.

Hyperlipidemia, characterized by elevated serum lipid concentrations resulting from lipid metabolism dysfunction, represents a prevalent global health concern. Ginsenoside Rb1, compound K (CK), and 20(S)-protopanaxadiol (PPD), bioactive constituents derived from Panax ginseng, have shown promise in mitigating lipid metabolism disorders. However, the comparative efficacy and underlying mechanisms of these compounds in hyperlipidemia prevention remain inadequately explored.

Nutritional, Textural, and Sensory Attributes of Protein Bars Formulated with Mycoproteins.

Research accumulated over the past decades has shown that mycoprotein could serve as a healthy and safe alternative protein source, offering a viable substitute for animal- and plant-derived proteins. This study evaluated the impact of substituting whey protein with fungal-derived mycoprotein at different levels (10%, 20%, and 30%) on the quality of high-protein nutrition bars (HPNBs). It focused on nutritional content, textural changes over storage, and sensory properties.

High-level production of Rhodiola rosea characteristic component rosavin from D-glucose and L-arabinose in engineered Escherichia coli.

Rosavin is the characteristic component of Rhodiola rosea L., an important medicinal plant used widely in the world that has been reported to possess multiple biological activities. However, the endangered status of wild Rhodiola has limited the supply of rosavin.

Reaction engineering blocks ether cleavage for synthesizing chiral cyclic hemiacetals catalyzed by unspecific peroxygenase.

Hemiacetal compounds are valuable building blocks in synthetic chemistry, but their enzymatic synthesis is limited and often hindered by the instability of hemiacetals in aqueous environments. Here, we show that this challenge can be addressed through reaction engineering by using immobilized peroxygenase from Agrocybe aegerita (AaeUPO) under neat reaction conditions, which allows for the selective C-H bond oxyfunctionalization of environmentally significant cyclic ethers to cyclic hemiacetals. A wide range of chiral cyclic hemiacetal products are prepared in >99% enantiomeric excess and 95170 turnover numbers of AaeUPO.

Standardized Iterative Genome Editing Method for Based on CRISPR-Cas9.

The introduction of complex biosynthetic pathways into the hosts' chromosomes is gaining attention with the development of synthetic biology. While CRISPR-Cas9 has been widely employed for gene knock-in, the process of multigene insertion remains cumbersome due to laborious and empirical gene cloning procedures. To address this, we devised a standardized iterative genome editing system for , harnessing the power of CRISPR-Cas9 and MetClo assembly.