Herein, we report an engineered enzyme that can monooxygenate unprotected tryptophan into the corresponding 3a-hydroxyhexahydropyrrolo[2,3-b]indole-2-carboxylic acid (HPIC) in a single, scalable step with excellent turnover number and diastereoselectivity. Taking advantage of directed evolution, we analyzed the stepwise oxygen-insertion mechanism of tryptophan 2,3-dioxygenases, and transformed tryptophan 2,3-dioxygenase from Xanthomonas campestris into a monooxygenase for oxidative cyclization of tryptophans. It was revealed that residue F51 is vital in determining the product ratio of HPIC to N'-formylkynurenine. Our reactions and purification procedures use no organic solvents, resulting in an eco-friendly method to prepare HPICs for further applications.
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http://dx.doi.org/10.1002/anie.201911825 | DOI Listing |
J Phys Chem Lett
January 2025
School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
Electrochemical nitrogen conversion for ammonia (NH) synthesis, driven by renewable electricity, offers a sustainable alternative to the traditional Haber-Bosch process. However, this conversion process remains limited by a low Faradaic efficiency (FE) and NH yield. Although transition metals have been widely studied as catalysts for NH synthesis through effective electron donation/back-donation mechanisms, there are challenges in electrochemical environments, including competitive hydrogen evolution reaction (HER) and catalyst stability issues.
View Article and Find Full Text PDFMol Cancer
January 2025
Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Background And Aims: Oncogenic KRAS mutations are present in approximately 90% of pancreatic ductal adenocarcinoma (PDAC). However, Kras mutation alone is insufficient to transform precancerous cells into metastatic PDAC. This study investigates how KRAS-mutated epithelial cells acquire the capacity to escape senescence or even immune clearance, thereby progressing to advanced PDAC.
View Article and Find Full Text PDFNat Microbiol
January 2025
School of Environmental and Chemical Engineering, Shanghai University, Shanghai, China.
Artificial intelligence (AI) is a promising approach to identify new antimicrobial compounds in diverse microbial species. Here we developed an AI-based, explainable deep learning model, EvoGradient, that predicts the potency of antimicrobial peptides (AMPs) and virtually modifies peptide sequences to produce more potent AMPs, akin to in silico directed evolution. We applied this model to peptides encoded in low-abundance human oral bacteria, resulting in the virtual evolution of 32 peptides into potent AMPs.
View Article and Find Full Text PDFSci Rep
January 2025
College of Art and Design, Shaanxi University of Science and Technology, Xi'an, 710021, China.
In recent years, the emergence of artificial intelligence painting tools has significantly changed the creative activities and future development of designers, but studies specifically addressing designers' inclinations to transition to AI painting tools are scarce. Therefore, to understand designers' switching intentions toward AI painting tools, this study proposed a research model based on the push-pull-mooring framework. Data were collected from 320 Chinese designers and analyzed using structural equation modeling.
View Article and Find Full Text PDFRisk Anal
January 2025
School of Political Science and Public Administration, Wuhan University, Wuhan, China.
The unpredictability of the epidemics caused by new, unknown viruses, combined with differing responsibilities among government departments, often leads to a prisoner's dilemma in epidemic information governance. In this context, the whistle-blower effect in the health departments leads to delayed reporting to avoid potential retaliation, and the cry-wolf effect in the administrative departments results in sustained observation to avoid ineffective warnings. To address these challenges, we employ game theory to analyze the dynamics of epidemic information governance and focus on two external governance mechanisms-superior accountability and media supervision-that can help resolve the prisoner's dilemma during and after an outbreak.
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