Understanding How a Key Enzyme Helps Create Health-Boosting Compounds in Ginseng

Jim Crocker
28th August, 2024

Understanding How a Key Enzyme Helps Create Health-Boosting Compounds in Ginseng

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Capital Medical University identified a new gene, PnUGT57, crucial for creating bioactive compounds in Panax notoginseng
  • PnUGT57 helps produce notoginsenosides, which have therapeutic benefits like antioxidant and anti-inflammatory effects
  • Key residues in PnUGT57 were identified, and specific mutations significantly improved the enzyme's activity, aiding future therapeutic applications
Panax notoginseng (Burk.) F.H. Chen, commonly known as Sanqi or Tianqi in China, is a traditional Chinese medicine with a wide range of pharmacological effects, including treatment for cardiovascular diseases, pain, inflammation, trauma, and internal and external bleeding due to injury[2]. Recent research from Capital Medical University has identified a new xylosyltransferase gene, PnUGT57 (named UGT94BW1), which plays a crucial role in the biosynthesis of notoginsenosides, the bioactive compounds in Panax notoginseng[1]. The study aimed to address the limited understanding of the xylosyltransferases involved in the generation of notoginsenosides, which has been a bottleneck in further studying their biosynthesis. Notoginsenosides are important because of their therapeutic potential, including antioxidant, anti-inflammatory, and neuroprotective effects[3][4][5]. The identification of PnUGT57 and its functional characterization represents a significant advancement in this field. Researchers first characterized the optimal conditions for PnUGT57 activity and its enzymatic kinetic parameters. They discovered that PnUGT57 could catalyze the 2'-O glycosylation of ginsenosides Rh1 and Rg1 to produce notoginsenosides R2 and R1, respectively. Glycosylation is a biochemical process where a sugar molecule is added to another molecule, in this case, adding xylose to ginsenosides. This process is critical for the formation of notoginsenosides, which have various pharmacological benefits. To understand the catalytic mechanism of PnUGT57, the researchers employed molecular docking and site-directed mutagenesis. Molecular docking is a method used to predict the interaction between molecules, while site-directed mutagenesis involves changing specific amino acids in a protein to study their function. The study identified key residues—Glu26, Ser266, Glu267, Trp347, Ser348, and Glu352—that are essential for the enzyme's activity. Furthermore, mutations at specific sites, such as PnUGT57R175A and PnUGT57G237A, significantly improved the enzyme's catalytic activity. These findings not only enhance the understanding of the biosynthesis of notoginsenosides but also provide valuable insights for the modification and application of xylosyltransferases in the future. This could lead to more efficient production of notoginsenosides, potentially making these compounds more accessible for therapeutic use. The study ties together earlier findings by expanding the understanding of the molecular mechanisms involved in the pharmacological effects of Panax notoginseng. For instance, previous research has shown that Panax notoginseng saponins (PNS) are effective in treating acute cerebral ischemia by regulating transcription factors and reducing inflammation[3]. The identification of PnUGT57 adds another layer of understanding by elucidating the biosynthetic pathway of these saponins. Moreover, the antioxidant properties of notoginsenoside R1 (NGR1), another component of Panax notoginseng, have been shown to protect against oxidative stress-induced mitochondrial damage and osteoblast dysfunction, which are critical in the progression of osteoporosis[4]. The current study's findings on the biosynthesis of notoginsenosides could facilitate the development of more effective treatments for such conditions. In conclusion, the identification and characterization of the PnUGT57 gene from Panax notoginseng by researchers at Capital Medical University represent a significant advancement in the understanding of notoginsenoside biosynthesis. This study not only provides a new xylosyltransferase gene but also offers insights into the enzyme's catalytic mechanism, paving the way for future research and potential therapeutic applications.

MedicineBiochemPlant Science

References

Main Study

1) Characterization of a Xylosyltransferase from Panax notoginseng Catalyzing Ginsenoside 2'-O Glycosylation in the Biosynthesis of Notoginsenosides.

Published 27th August, 2024

https://doi.org/10.1021/acs.jnatprod.4c00298

Related Studies

2) Traditional uses, botany, phytochemistry, pharmacology and toxicology of Panax notoginseng (Burk.) F.H. Chen: A review.

https://doi.org/10.1016/j.jep.2016.05.005

3) Proteomics and transcriptome reveal the key transcription factors mediating the protection of Panax notoginseng saponins (PNS) against cerebral ischemia/reperfusion injury.

https://doi.org/10.1016/j.phymed.2021.153613

4) Notoginsenoside R1 attenuates oxidative stress-induced osteoblast dysfunction through JNK signalling pathway.

https://doi.org/10.1111/jcmm.17054

5) Notoginsenoside R1 Improves Cerebral Ischemia/Reperfusion Injury by Promoting Neurogenesis via the BDNF/Akt/CREB Pathway.

https://doi.org/10.3389/fphar.2021.615998


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