Biomedical subjects

Qing Zhao

Publications and source records attributed to Qing Zhao.

3 recordsLinked to original sources

PubMed2026

Identification and Catalytic Optimization of Pinene Oxidases in Paeoniflorin Biosynthetic Pathway.

Paeoniflorin is a pharmacologically important cage-like monoterpene glycoside characteristic of Paeonia plants, yet its biosynthetic pathway has remained largely unresolved, hindering sustainable production. Here, we confirmed that paeoniflorin biosynthesis originates from α-pinene and identified three novel cytochrome P450 enzymes that catalyze pinene oxidation. CYP71AN126 catalyzes the hydroxylation of α-pinene at positions C4 and C10, followed by further oxidation of the alcohol to a ketone at C4, whereas CYP76A225/226 exclusively catalyze C10 hydroxylation. Virus-induced gene silencing (VIGS) assays demonstrated that silencing CYP71AN126, but not CYP76A225 and CYP76A226, significantly reduced the paeoniflorin content, indicating that C4 hydroxylation plays an important role in paeoniflorin biosynthesis, whereas C10 hydroxylation is not. Through the analysis of natural sequence and activity divergence among CYP71AN126 and CYP76A225/226, combined with protein structure prediction and site-directed mutagenesis, we identified L493 as a critical residue involved in regulating catalytic site specificity and substrate specificity of CYP71AN126. Mutation of L493 reduced or eliminated the formation of undesired C10 hydroxylation side-product and enhanced substrate specificity. These findings establish C4 oxidation of α-pinene as the critical committed step in paeoniflorin biosynthesis. Our study lays a foundation for elucidating the complete biosynthetic pathway of paeoniflorin in Paeonia and provides a target for enzyme engineering of CYP71AN126 aimed at the efficient production of paeoniflorin via synthetic biology approaches.

Paeonia genus↗

PubMed2026

In silico analysis based on network pharmacology and biomolecular informatics to explore the mechanism of action of Erjing Pills (from Shengji Zonglu) in the treatment of leukotrichia.

This study aimed to explore the core active ingredients and potential molecular mechanisms of Erjing Pills, a prescription in the classic work of Traditional Chinese Medicine, "Shengji Zonglu," in the treatment of leukotrichia by utilizing network pharmacology and biomolecular docking techniques. The chemical components and potential targets of Chinese herbal medicines were analyzed through databases such as the Traditional Chinese Medicine Systems Pharmacology Database. The targets related to leukotrichia were collected using GeneCards. The intersection targets were obtained using RStudio. The protein-protein interaction (PPI) network map and the "drug-component-target-disease" visualization network were generated using Cytoscape and STRING to screen the core components and key targets. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were carried out using the Database for Annotation, Visualization and Integrated Discovery and RStudio. Finally, molecular docking verification was performed by AutoDock and PyMOL (Schrödinger LLC). The key active ingredients of Erjing Pills in the treatment of leukotrichia are β-sitosterol, quercetin, baicalein, and stigmasterol. The top 5 PPI core target proteins, in order, are AKT serine/threonine kinase 1, interleukin 6, tumor protein p53, cysteine-aspartic acid protease 3, and interleukin 1 beta. The Gene Ontology enrichment analysis suggests that the biological processes mainly include responses to exogenous stimuli, membrane rafts, and DNA-binding transcription factor binding. The Kyoto Encyclopedia of Genes and Genomes pathways involve signal pathways such as lipid and atherosclerosis, hepatitis B, Kaposi sarcoma virus infection, chemical carcinogenesis, and human cytomegalovirus infection. The molecular docking results indicate that most of the main active ingredients in Erjing Pills have relatively stable binding activities with the key targets, such as AKT serine/threonine kinase 1, interleukin 6, tumor protein p53, cysteine-aspartic acid protease 3, and interleukin 1 beta, in the PPI network. The active ingredients of Erjing Pills may interfere with the pathological process of leukotrichia by regulating key targets and signal pathways. This study provides a theoretical basis for the clinical application of Erjing Pills and indicates the direction for subsequent experimental research.

Drugs, Chinese Herbal↗

PubMed2025

The chloroplast 16S rRNA dimethyltransferase BrPFC1 is required for Brassica rapa development under chilling stress.

Chloroplast ribosomal RNA (Ch-rRNA) methylation is critical for plant development and response to low temperatures. Several Ch-rRNA methyltransferases and their catalytic modes, as well as biological relevance, have been reported in model plant species. However, Ch-rRNA methyltransferases and their functional significance remain poorly characterized in crops, including leafy vegetables such as Chinese cabbage. In this study, we screened an EMS-mutagenized Chinese cabbage population and identified a yellow inner leaf (yif) mutant. This mutant develops yellowing inner leaves with reduced chlorophyll accumulation and ultrastructure-impaired chloroplasts under low-temperature conditions. Genetic analysis revealed a premature termination mutation in BrPFC1, encoding the chloroplast-localized 16S rRNA dimethyltransferase. The BrPFC1 mutation (yif) disrupts the dimethylation of 16S rRNA. The cold-sensitive phenotype of the yif mutant can be explained by temperature-dependent defects in the maturation and assembly of chloroplast ribosomes at 4°C. Through integrated analysis of chloroplast and nuclear transcriptomes coupled with translational profiling at 25°C and 4°C, we established that low temperature preferentially upregulates transcripts encoding nuclear-derived ribosomal proteins, while defective 16S rRNA specifically compromises the translational efficiency of chloroplast-encoded photosynthetic complex and ribosomal protein at 4°C. These findings establish rRNA modification by BrPFC1 as a critical regulatory layer for optimizing chloroplast translational efficiency at 4°C, providing mechanistic insights into post-translational adaptation strategies in Chinese cabbage.

Chloroplasts↗