Publications by authors named "Xinxiao Sun"

Nucleosides and its derivatives are essential chemicals with extensive applications in the food, agricultural, and pharmaceutical industries. Chemical synthesis of these compounds often faces problems such as harsh reaction conditions and environmental pollution, whereas microbial synthesis provides a promising and sustainable alternative. This review discusses recent advances in the biosynthesis of nucleosides and their derivatives.

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Article Synopsis
  • The GPx1 gene plays a crucial role in maintaining cellular redox balance, and changes in its expression are associated with cancer progression.
  • Researchers used computational tools to identify harmful non-synonymous single nucleotide polymorphisms (nsSNPs) in the GPx1 gene that could affect the enzyme's structure and function.
  • The final analysis highlighted three specific mutations that showed reduced binding and stability when interacting with TRAF2, suggesting their potential connection to cancer development.
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1,5-Pentanediol (1,5-PDO) is an important five-carbon alcohol, widely used in polymer and pharmaceutical industries. Considering the substantial energy (ATP and NADPH) requirements of previous pathways, an energy-conserving artificial pathway with a higher theoretical yield (0.75 mol/mol glucose) was designed and constructed in this study.

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Enhanced production stability and efficiency along with a decrease in production costs are required to build efficient microbial cell factories. Target genes can be integrated into the genome to enhance genetic stability, reduce reliance on antibiotics, and alleviate the metabolic burden. However, selecting the optimal insertion site for the desired gene expression levels remains challenging.

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Salicin is a natural glycoside compound widely used to treat fever, inflammation, and analgesia. Currently, salicin is primarily extracted from willow bark, which is not only cumbersome in terms of extraction and separate steps, but also subject to seasonal and geographic limitations. In this study, a highly efficient biosynthetic pathway for salicin synthesis was designed and constructed in E.

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  • Coumarins are a large group of natural compounds with various biological benefits, and Cinnamyl-CoA ortho-hydroxylases (CCHs) are crucial for their production as they control the main step in their biosynthesis.* -
  • Engineering CCHs is difficult because of their large substrates and unclear relationships between structure and function, but this study improved a specific CCH from Arabidopsis thaliana through directed evolution and structural adjustments.* -
  • The engineered CCHs, combined with optimized biosynthetic processes, significantly boosted the production of simple coumarins and their glucosides, achieving impressive increases in yield, particularly with aesculin during fermentation.*
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Lignocellulose is the most abundant renewable resource on earth. Constructing microbial cell factories for synthesizing value-added chemicals with lignocellulose is the key to realize green biomanufacturing. Xylose is the second most fermentable sugar in lignocellulose after glucose.

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Arbutin, a glycosylated compound of hydroquinone, exists in two forms of β-arbutin and α-arbutin based on the configuration of the glycosidic bond. As a safe and stable whitening agent, arbutin is widely used in cosmetics, and it has antioxidant, antimicrobial, anti-inflammatory, and anti-tumor activities. The production of arbutin by plant extraction faces challenges such as long plant growth periods, complex extraction processes, and low yields.

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The widespread use of polymers has made our lives increasingly convenient by offering a more convenient and dependable material. However, the challenge of efficiently decomposing these materials has resulted in a surge of polymer waste, posing environment and health risk. Currently, landfill and incineration treatment approaches have notable shortcomings, prompting a shift towards more eco-friendly and sustainable biodegradation approaches.

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Gallic acid (GA) and β-glucogallin (BGG) are natural products with diverse uses in pharmaceutical, food, chemical and cosmetic industries. They are valued for their wide-ranging properties such as antioxidant, antibacterial, antidiabetic, and anticancer properties. Despite their significant importance, microbial production of GA and BGG faces challenges such as limited titers and yields, along with the incomplete understanding of BGG biosynthesis pathways in microorganisms.

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Enzymes play a pivotal role in various industries by enabling efficient, eco-friendly, and sustainable chemical processes. However, the low turnover rates and poor substrate selectivity of enzymes limit their large-scale applications. Rational computational enzyme design, facilitated by computational algorithms, offers a more targeted and less labor-intensive approach.

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Hydroxylated aromatic compounds exhibit exceptional biological activities. In the biosynthesis of these compounds, three types of hydroxylases are commonly employed: cytochrome P450 (CYP450), pterin-dependent monooxygenase (PDM), and flavin-dependent monooxygenase (FDM). Among these, FDM is a preferred choice due to its small molecular weight, stable expression in both prokaryotic and eukaryotic fermentation systems, and a relatively high concentration of necessary cofactors.

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Butyrolactam, a crucial four-carbon molecule, serves as building block in synthesis of polyamides. While biosynthesis of butyrolactam from renewable carbon sources offers a more sustainable approach, it has faced challenges in achieving high product titer and yield. Here, an efficient microbial platform for butyrolactam production was constructed by elimination of rate-limiting step and systematic pathway optimization.

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Background: Lignocellulose, the most abundant non-edible feedstock on Earth, holds substantial potential for eco-friendly chemicals, fuels, and pharmaceuticals production. Glucose, xylose, and arabinose are primary components in lignocellulose, and their efficient conversion into high-value products is vital for economic viability. While glucose and xylose have been explored for such purpose, arabinose has been relatively overlooked.

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Horse chestnut (Aesculus chinensis) is an important medicinal tree that contains various bioactive compounds, such as aescin, barrigenol-type triterpenoid saponins (BAT), and aesculin, a glycosylated coumarin. Herein, we report a 470.02 Mb genome assembly and characterize an Aesculus-specific whole-genome duplication event, which leads to the formation and duplication of two triterpenoid biosynthesis-related gene clusters (BGCs).

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β-Arbutin is a plant-derived glycoside and widely used in cosmetic and pharmaceutical industries because of its safe and effective skin-lightening property as well as anti-oxidant, anti-microbial, and anti-inflammatory activities. In recent years, microbial fermentation has become a highly promising method for the production of β-arbutin. However, this method suffers from low titer and low yield, which has become the bottleneck for its widely industrial application.

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Phosphorus, an indispensable nutrient, plays an essential role in cell composition, metabolism, and signal transduction. When inorganic phosphorus (Pi) is scarce, the Pi starvation response in E. coli is activated to increase phosphorus acquisition and drive the cells into a non-growing state to reduce phosphorus consumption.

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p-Hydroxyacetophenone (p-HAP) and its glucoside picein are plant-derived natural products that have been extensively used in chemical, pharmaceutical and cosmetic industries owing to their antioxidant, antibacterial and antiseptic activities. However, the natural biosynthetic pathways for p-HAP and picein have yet been resolved so far, limiting their biosynthesis in microorganisms. In this study, we design and construct a biosynthetic pathway for de novo production of p-HAP and picein from glucose in E.

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Vanillyl alcohol is a precursor of vanillin, which is one of the most widely used flavor compounds. Currently, vanillyl alcohol biosynthesis still encounters the problem of low efficiency. In this study, coculture engineering was adopted to improve production efficiency of vanillyl alcohol in .

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Biodiesel production has increased significantly in recent years, leading to an increase in the production of crude glycerol. In this study, a novel growth-coupled erythrose 4-phosphate (E4P) formation strategy that can be used to produce high levels of β-arbutin using engineered Escherichia coli and glycerol as the carbon source was developed. In the strategy, E4P formation was coupled with cell growth, and a growth-driving force made the E4P formation efficient.

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Plant-derived cytochrome P450-dependent flavonoid 3'-hydroxylases are the rate-limiting enzymes in flavonoid biosynthesis. In this study, the large component (HpaB) of a prokaryotic 4-hydroxyphenylacetate (4-HPA) 3-hydroxylase was engineered for efficient 3'-hydroxylation of naringenin. First, we selected four HpaBs through database search and phylogenetic analysis and compared their catalytic activities toward 4-HPA and naringenin.

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Orotate (OA) is a precursor of pyrimidine nucleotides and is widely used in food, pharmaceutical, and cosmetic industries. Although various microorganisms have been used for OA production, the production efficiency needs to be further improved for industrial application. In this study, we engineered Escherichia coli native metabolism for efficient OA production.

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α-Aminoadipic acid (AAA) is a nonproteinogenic amino acid with potential applications in pharmaceutical, chemical and animal feed industries. Currently, AAA is produced by chemical synthesis, which suffers from high cost and low production efficiency. In this study, we engineered Escherichia coli for high-level AAA production by coupling lysine biosynthesis and degradation pathways.

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Dencichine is a plant-derived nature product that has found various pharmacological applications. Currently, its natural biosynthetic pathway is still elusive, posing challenge to its heterologous biosynthesis. In this work, we design artificial pathways through retro-biosynthesis approaches and achieve de novo production of dencichine.

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Ferulic acid (FA) is a natural methylated phenolic acid which represents various bioactivities. Bioproduction of FA suffers from insufficient methyl donor supplement and inefficient hydroxylation. To overcome these hurdles, we first activate the S-adenosylmethionine (SAM) cycle in E.

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