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[学术文献 ] Insights into the zearalenone degradation performance and pathway by Gordonia hydrophobica HAU421 and characterization of a novel lactonohydrolase involved 进入全文
International Journal of Biological Macromolecules
Zearalenone (ZEN) is a harmful macrolide mycotoxin, posing a serious hazard to human health. In this study, a highly efficient ZEN-degrading bacterium Gordonia hydrophobica HAU421 was isolated from soil by using spiramycin (SPM)-containing selective medium. Mass spectrometry analysis revealed that strain HAU421 could transform ZEN into hydrolyzed zearalenone (HZEN), zearalenol (ZEL), and hydrolyzed zearalenol (HZEL). A novel lactonohydrolase GhZH capable of hydrolyzing ZEN was mined from the genome of strain HAU421 and heterologously expressed in Escherichia coli. The recombinant GhZH exhibited peak activity at pH 7.0 and 42 °C. The catalytic triad of GhZH was identified as S122-D147-H297 via sequence comparison, molecular docking and site-directed mutagenesis. Moreover, toxicological analysis suggested that GhZH-catalyzed ZEN hydrolyzation resulted in the detoxification of its hepatotoxicity. To meet the industrial demands, GhZH was immobilized onto chitosan microspheres using the crosslinker glutaraldehyde. The stability of immobilized GhZH at harsh acidic pH and high temperature was enhanced in comparison with free GhZH. The immobilized GhZH achieved a ZEN removal rate of 53.2 % in beer and 74.0 % in corn steep liquor. These findings offer new insights into microbial ZEN degradation and support the advancement of enzyme-catalyzed ZEN detoxification.
[学术文献 ] Efficient Expression and Activity Optimization of Manganese Peroxidase for the Simultaneous Degradation of Aflatoxins AFB1, AFB2, AFG1, and AFG2 进入全文
Journal of Agricultural and Food Chemistry
Aflatoxins (AFs), notorious mycotoxins that pose significant risks to human and animal health, make biodegradation extremely crucial as they offer a promising approach to managing and reducing their harmful impacts. In this study, we identified a manganese peroxidase from Punctularia strigosozonata (PsMnp) through protein similarity analysis, which has the capability to degrade four AFs (AFB1, AFB2, AFG1, and AFG2) simultaneously. The gene encoding this enzyme was subject to codon optimization, followed by cold shock induction expression using the pColdII vector, leading to the soluble expression of manganese peroxidase (Mnp) in Escherichia coli. This study tackled the problem of inclusion body formation that often occurs during Mnp expression in E. coli. After optimizing the degradation conditions, the degradation rates for AFB1, AFB2, AFG1, and AFG2 were 87.9, 72.8, 77.3, and 85.6%, respectively. Molecular docking and molecular dynamics simulations indicated that PsMnp facilitated the degradation of AFs through hydrophobic and polar interactions among various amino acid residues. This research offers novel insights into the rapid discovery of enzymes capable of degrading AFs and establishes a theoretical foundation for the efficient expression of mycotoxin detoxification enzymes.
[学术文献 ] Metabolic Engineering of Corynebacterium glutamicum for High-Level Production of 1,5-Pentanediol, a C5 Diol Platform Chemical 进入全文
Advanced Science
The biobased production of chemicals is essential for advancing a sustainable chemical industry. 1,5-Pentanediol (1,5-PDO), a five-carbon diol with considerable industrial relevance, has shown limited microbial production efficiency until now. This study presents the development and optimization of a microbial system to produce 1,5-PDO from glucose in Corynebacterium glutamicum via the l-lysine-derived pathway. Engineering began with creating a strain capable of producing 5-hydroxyvaleric acid (5-HV), a key precursor to 1,5-PDO, by incorporating enzymes from Pseudomonas putida (DavB, DavA, and DavT) and Escherichia coli (YahK). Two conversion pathways for further converting 5-HV to 1,5-PDO are evaluated, with the CoA-independent pathway—utilizing Mycobacterium marinum carboxylic acid reductase (CAR) and E. coli YqhD—proving greater efficiency. Further optimization continues with chromosomal integration of the 5-HV module, increasing 1,5-PDO production to 5.48 g L−1. An additional screening of 13 CARs identifies Mycobacterium avium K-10 (MAP1040) as the most effective, and its engineered M296E mutant further increases production to 23.5 g L−1. A deep-learning analysis reveals that Gluconobacter oxydans GOX1801 resolves the limitations of NADPH, allowing the final strain to produce 43.4 g L−1 1,5-PDO without 5-HV accumulation in fed-batch fermentation. This study demonstrates systematic approaches to optimizing microbial biosynthesis, positioning C. glutamicum as a promising platform for sustainable 1,5-PDO production.
[学术文献 ] Recent advances in bioinspired multienzyme engineering for food applications 进入全文
Trends in Food Science & Technology
Bioinspired multienzyme engineering provides strong technical support for enhancing food quality, safety, and nutrition. Summarizing and examining its applications and progress in the food industry are essential for exploring the future of food development. Inspired by efficient catalysis of nature at complex reactions, bioinspired multienzyme engineering leveraging the synergistic action of multiple enzymes to achieve targeted outcomes in food processing and analysis. This paper reviews the latest advancements in bioinspired multienzyme engineering within the food sector, highlighting its core operational principles and applications. It provides a systematic analysis of diverse bioinspired multienzyme engineering approaches, exploring assembly strategies, interaction types, and techniques to enhance the enzymes' functionality and catalytic efficiency. The discussion also covers the technology's applications in food biosynthesis, quality monitoring, contaminant degradation, and packaging enhancement. Bioinspired multienzyme engineering is revolutionizing the food industry with its efficiency and eco-friendliness. As protein engineering, synthetic biology, artificial intelligence and machine learning advance, bioinspired multienzyme engineering promises to address stability, activity, scalability, and regulatory challenges, broadening its applications from bioactive compound production and biosensor design to contaminant degradation and smart packaging.
[学术文献 ] Chemoenzymatic Synthesis Planning Guided by Reaction Type Score 进入全文
Journal of Chemical Information and Modeling
Thanks to the growing interest in computer-aided synthesis planning (CASP), a wide variety of retrosynthesis and retrobiosynthesis tools have been developed in the past decades. However, synthesis planning tools for multistep chemoenzymatic reactions are still rare despite the widespread use of enzymatic reactions in chemical synthesis. Herein, we report a reaction type score (RTscore)-guided chemoenzymatic synthesis planning (RTS-CESP) strategy. Briefly, the RTscore is trained using a text-based convolutional neural network (TextCNN) to distinguish synthesis reactions from decomposition reactions and evaluate synthesis efficiency. Once multiple chemical synthesis routes are generated by a retrosynthesis tool for a target molecule, RTscore is used to rank them and find the step(s) that can be replaced by enzymatic reactions to improve synthesis efficiency. As proof of concept, RTS-CESP was applied to 10 molecules with known chemoenzymatic synthesis routes in the literature and was able to predict all of them with six being the top-ranked routes. Moreover, RTS-CESP was employed for 1000 molecules in the boutique database and was able to predict the chemoenzymatic synthesis routes for 554 molecules, outperforming ASKCOS, a state-of-the-art chemoenzymatic synthesis planning tool. Finally, RTS-CESP was used to design a new chemoenzymatic synthesis route for the FDA-approved drug Alclofenac, which was shorter than the literature-reported route and has been experimentally validated.
[前沿资讯 ] 科学家发展AI赋能的蛋白质理性设计新方法 进入全文
科学网
华东理工大学生物反应器工程国家重点实验室教授郁惠蕾、许建和团队，利用人工智能（AI）赋能的蛋白质理性设计技术重塑了羧酸还原酶的活性中心，大幅提升羧酸还原酶的活性和底物专一性，并成功应用于尼龙6和尼龙66的单体（1,6-己二胺和6-氨基己酸）的生物合成中。相关研究发表于《科学进展》。 研究团队发展了AI赋能的蛋白质理性设计新方法，构建了基于近攻击构象概率和酶-底物结合能的物理模型，并利用Rosetta Design对活性中心多个位点的庞大组合突变体库进行了高效精准的设计和评价，实现了酶活性中心大范围协同突变的“功能重塑”。实验结果显示，人工设计的突变体酶对底物6-氨基己酸的催化效率提升101倍，对底物1,6-己二酸的催化效率提升14倍且底物专一性提高86倍。最终，由1,6-己二酸出发合成的尼龙前体6-氨基己酸和1,6-己二胺，生产强度分别达到文献报道最高值的13.3倍和12倍。
