Research progress in synthetic biology of active compounds in Chinese medicinal plants / 中国中药杂志

Mecicinal plants boast abundant natural compounds with significant pharmacological activity, and such compounds, featuring diversified and complex structures, can be used for research and development of drugs. At present, these natural compounds are directly extracted from herbs which, however, suffer from damaged wild resources and shortage of planting resources attributing to the increasing demand. Moreover, the low content in medicinal plants and complex structures are another challenge to the research and development of drugs. Heterologous synthesis with synthetic biology methods is a solution that has attracted wide attention. Synthetic bio-logy for the production of natural active compounds in Chinese medicinal plants involves the exploration of key enzymes in compound bio-synthetic pathways from plants, analysis of enzyme functions and mechanisms, and reconstruction and optimization of biosynthetic pathways in microorganisms for efficient synthesis of compounds. This study briefed the development process of synthetic biology and the biosynthetic pathways of terpenoids, alkaloids, and flavonoids, and summarized the related strategies of synthetic biology such as the reconstruction and optimization of metabolic pathways, regulation of fermentation process, and strain improvement, and the latest applications of heterogeneous synthetic biology in the production of natural compounds from Chinese medicinals. This study is expected to serve as a reference for the efficient production of terpenoids, alkaloids, flavonoids, and other active compounds from Chinese medicinal plants with strategies of synthetic biology.

Differential expression of the TwHMGS gene and its effect on triptolide biosynthesis in Tripterygium wilfordii / 中国天然药物

3-Hydroxy-3-methylglutaryl-CoA synthase (HMGS) is the first committed enzyme in the MVA pathway and involved in the biosynthesis of terpenes in Tripterygium wilfordii. The full-length cDNA and a 515 bp RNAi target fragment of TwHMGS were ligated into the pH7WG2D and pK7GWIWG2D vectors to respectively overexpress and silence, TwHMGS was overexpressed and silenced in T. wilfordii suspension cells using biolistic-gun mediated transformation, which resulted in 2-fold increase and a drop to 70% in the expression level compared to cells with empty vector controls. During TwHMGS overexpression, the expression of TwHMGR, TwDXR and TwTPS7v2 was significantly upregulated to the control. In the RNAi group, the expression of TwHMGR, TwDXS, TwDXR and TwMCT visibly displayed downregulation to the control. The cells with TwHMGS overexpressed produced twice higher than the control value. These results proved that differential expression of TwHMGS determined the production of triptolide in T. wilfordii and laterally caused different trends of relative gene expression in the terpene biosynthetic pathway. Finally, the substrate acetyl-CoA was docked into the active site of TwHMGS, suggesting the key residues including His247, Lys256 and Arg296 undergo electrostatic or H-bond interactions with acetyl-CoA.

Insights into structure and function of diterpene synthases in plants / 药学学报

Diterpene synthases from plants are key enzymes in diterpene biosynthesis, which catalyzed the initial cyclization cascade of (E,E,E,)-geranylgeranyl pyrophosphate, and generated diverse carbon skeletons. Recent research show that the structural and stereo chemical differences lead to diverse natural diterpene compounds of plants. The structures of diterpene synthases play a crucial role in cyclization function. This article mainly reviews the mechanisms, functional characteristics, and structural information of diterpene synthases according to the crystal structures and functions.

Cloning and protein expression analysis of monoterpene synthase gene TwMS in Tripterygium wilfordii / 中国中药杂志

In this study, we cloned a monoterpene synthases, TwMS from Tripterygium wilfordii suspension cells. TwMS gene contained a 1 797 bp open reading frame (ORF), encoding a polypeptide of 579 amino acids, which deduced isoelectric point (pI) was 6.10 and the calculated molecular weight was 69.75 kDa. Bioinformation analysis showed that the sequence of TwMS was consistent with the feature of monoterpene synthases. Differential expression analysis revealed that the relative expression level of TwMS increased significantly after being induced by methyl jasmonate (MeJA). The highest expression level occurred at 24 h. TwMS protein was successfully expressed in Escherichia coli BL21 (DE3), which laid the foundation for identifying the function of T. wilfordii monoterpene synthases.

Cloning and protein expression analysis of geranyl diphosphate synthase genes in Tripterygium wilfordii / 中国中药杂志

Based on the transcriptome data, the study cloned full-length cDNA of TwGPPS1 and TwGPPS2 genes from Tripterygium wilfordii suspension cells and then analyzed the bioinformation of the sequence and protein expression. The cloned TwGPPS1 has a 1 278 bp open reading frame (ORF) encoding a polypeptide of 425 amino acids. The deduced isoelectric point (pI) was 6.68, a calculated molecular weight was about 47.189 kDa. The full-length cDNA of the TwGPPS2 contains a 1 269 bp open reading frame (ORF) encoding a polypeptide of 422 amino acids. The deduced isoelectric point (pI) was 6.71, a calculated molecular weight was about 46.774 kDa.The entire reading frame of TwGPPS1,2 was cloned into the pET-32a(+) vector and expressed in E. coli BL21 (DE3) cells to obtain the TwGPPS protein, which laid a basis for further study on the regulation of terpenoid secondary metabolism and biological synthesis.

Cloning and protein expression of sterol-C-24-methyl transferase 2 in Tripterygium wilfordii / 药学学报

24-Alkyl sterols are the major players in the control of membrane component and plant growth. In this paper, we cloned an important rate-limiting enzyme:sterol-C-24-methyl transferase (SMT) in the sterol biosynthetic pathway according to the transcriptome data of Tripterygium wilfordii. suspension cells, whose full-length cDNA was 1 631 bp with an open reading frame of 1 080 bp, encoding a protein of 359 amino acids. It was estimated that theoretical isoelectric point (pI) was 6.43 and the molecular mass was 40.0 kDa. Bioinformatics analysis attributed the SMT gene to SMT2 family. The expression vector was constructed as the pMAL-c2x-TwSMT2 plasmid and the recombinant protein was expressed in E. coil BL21 (DE3) competent cells. After methyl jasmonate treatment, the relative expression level of TwSMT2 has improved significantly in 24 h. SDS-PAGE electrophoresis and Western Blot showed that protein of TwSMT2 in BL21 (DE3) strain was expressed after induction by IPTG. In this study, TwSMT2 was cloned for the first time and the recombinant protein was expressed, which lay the foundation for elucidation of the sterol biosynthetic pathway of Tripterygium wilfordii in the future.

Cloning and expression analysis of squalene synthase gene in Tripterygium wilfordii / 药学学报

In this paper, we cloned the full-length cDNA of TwSQS from Tripterygium wilfordii suspension cells (GenBank:KR401220) and performed the bioinformation and mRNA expression analysis. The expression after methyl jasmonate (MJ) treatment of the gene was detected by RT-PCR. The full-length cDNA of TwSQS was 1800 bp containing a 1242 bp open reading frame (ORF) encoding a polypeptide of 413 amino acids. The theoretical isoelectric point (pI) was 7.94 and the calculate molecular weight was about 47.20 kD. The relative expression level of TwSQS was deduced by MJ and reached the highest at 4 h after the treatment. The gene information we got in this study enriched the biosynthesis pathway of triterpenoids in Tripterygium wilfordii and laid foundation for further studies.

Cloning and bioinformatics analysis of geranylgeranyl diphosphate synthase gene of Tripterygium wilfordii / 中国中药杂志

A full-length cDNA of GGPPS gene from Tripterygium wilfordii suspension cells was obtained by use of RACE strategy (GeneBank: KM978333), and then analyzed by bioinformatics approaches. TwGGPPS cDNA has 1857 nucleotides and an open reading frame (ORF) encoding a protein of 514 amino acid residues. The deduced protein has isoelectric point (pI) of 7.85, a calculated molecular weight about 57.13 kD, 5 conserved domains and 2 functional domains. PSORT Prediction showed it was located at plasma membrane. Phylogenetic analysis demonstrated that TwGGPPS1 was similar to GGPPS from other species of plants. For the first time the cloning of geranylgeranyl diphosphate synthase gene from T. wilfordii was reported, it lays the foundation for further research of diterpenoids biosynthetic pathway.

Cloning and expression analysis of 4- (cytidine-5-diphospho) -2-C-methyl-D-erythritol kinase gene in Tripterygium wilfordii / 中国中药杂志

4-(Cytidine-5-diphospho) -2-C-methyl-D-erythritol kinase is a key enzyme in the biosynthesis pathway of terpenoids. According to the transcriptome database, the specific primers were designed and used in PCR. The bioinformatic analysis of the sequenced TwCMK gene was performed in several bioinformatics software. The Real-time fluorescence quantification polymerase chain reaction (RT-qPCR) were used to detect the expression levels of TwCMK from T. wilfordii after elicitor MeJA supplied. The results showed that the full length of TwCMK cDNA was 1 732 bp encoding 387 amino acids. The theoretical isoelectric point of the putative TwCMK protein was 5.79 and the molecular weight was about 42.85 kDa. MeJA stimulated the rising of TwCMK expression in suspension cell and signally impacted at 24 h. The research provides a basis for further study on the regulation of terpenoid secondary metabolism and biological synthesis.

Cloning and expression analysis of 2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase gene in Tripterygium wilfordii / 中国中药杂志

To clone the 2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase (TwMCT) full length cDNA from Tripterygium wilfordii, the specific primers were designed according to the transcriptome data and the LCPCR were carried out. After a series of bioinformatics analysis on the TwMCT, the MeJA induced expression content were investigated by real-time fluorescence quantification polymerase chain reaction (RT-qPCR). The result showed that the full of TwMCTcDNA was 1 318 bp nucleotides encoding 311 amino acids. The molecular weight of the deduced TwMCT protein was about 34.14 kDa and the theoretical isoelectric point was 8.65. Result of the RT-qPCR analysis indicated that the content of TwMCT mRNA expression in T. wilfordii suspension cell was rising after treating with MeJA and reached the maximum in 24 h. Cloning and analyzing TwMCT gene from T. wilfordii provided gene element for studying the function and expression regulation of secondary metabolites.