Abstract:Triterpenoid saponins are the class of secondary metabolites, synthesized via isoprenoid pathway. Oxidosqualene cyclases (OSCs) catalyzes the cyclization of 2, 3-oxidosqualene to various triterpene skeletons, the first committed step in triterpenoid biosynthesis. A full-length oxidosqualene cyclase cDNA from Bacopa monniera (BmOSC) was isolated and characterized. The open reading frame (ORF) of BmOSC consists of 2,292 bp, encoding 764 amino acid residues with an apparent molecular mass of 87.62 kDa and theoret… Show more
“…We chose BmOSC (Accession number. HM769762.1) as a control, which did not meet any of our screening criteria but was annotated as “putative β-AS” in a previous study …”
Section: Results
and Discussionmentioning
confidence: 99%
“…Lots of triterpenoids, especially ursolic acid and oleanolic acid were main components of apple peels, which were catalyzed by CYP450 enzyme with α-amyrin and β-amyrin as precursors, respectively , Phylogenetic analysis revealed that BmOSC is closely related with other plant OSCs, especially mixed α-AS, suggesting that BmOSC may be involved in formation of pentacyclic triterpenoids.…”
mentioning
confidence: 99%
“…34 Bacopa monniera belongs to Scrophulariaceae, which has lots of active pharmaceutical ingredient, such as glycoside, flavonoids, saponins and bacosides in its stolon, leaves and roots. 35,36 Phylogenetic analysis revealed that BmOSC is closely related with other plant OSCs, especially mixed α-AS, suggesting that BmOSC may be involved in formation of pentacyclic triterpenoids.…”
α-Amyrin is a plant-derived pentacyclic triterpenoid, with a lot of important physiological and pharmacological activities. The formation of α-amyrin from (3 S)-2,3-oxidosqualene is catalyzed by α-amyrin synthase (α-AS), a member of the oxidosqualene cyclase (OSC) protein family. However, α-amyrin is not yet commercially developed due to its extremely low productivity in plants. The engineered Saccharomyces cerevisiae with efficient α-amyrin production pathway could be used as an alternative and sustainable solution to produce α-amyrin from renewable raw materials. To efficiently improve α-amyrin production in S. cerevisiae, we identified two α-ASs, EjAS and MdOSC1 from Eriobotrya japonica and Malus × domestica, respectively, through strict bioinformatics screening criteria and phylogenetic analysis. The specific activities of purified EjAS and MdOSC1 were 0.0032 and 0.0293 μmol/min/mg, respectively. EjAS produced α-amyrin and β-amyrin at a ratio of 17:3, MdOSC1 produced α-amyrin, β-amyrin and lupeol at a ratio of 86:13:1, indicating MdOSC1 had significantly higher specific activity and higher ratio of α-amyrin than EjAS. Furthermore, MdOSC1 was introduced into S. cerevisiae combining with the increased supply of (3 S)-2,3-oxidosqualene to achieve the encouraging α-amyrin production, and the titer of α-amyrin achieved 11.97 ± 0.61 mg/L, 5.8 folds of the maximum production reported.
“…We chose BmOSC (Accession number. HM769762.1) as a control, which did not meet any of our screening criteria but was annotated as “putative β-AS” in a previous study …”
Section: Results
and Discussionmentioning
confidence: 99%
“…Lots of triterpenoids, especially ursolic acid and oleanolic acid were main components of apple peels, which were catalyzed by CYP450 enzyme with α-amyrin and β-amyrin as precursors, respectively , Phylogenetic analysis revealed that BmOSC is closely related with other plant OSCs, especially mixed α-AS, suggesting that BmOSC may be involved in formation of pentacyclic triterpenoids.…”
mentioning
confidence: 99%
“…34 Bacopa monniera belongs to Scrophulariaceae, which has lots of active pharmaceutical ingredient, such as glycoside, flavonoids, saponins and bacosides in its stolon, leaves and roots. 35,36 Phylogenetic analysis revealed that BmOSC is closely related with other plant OSCs, especially mixed α-AS, suggesting that BmOSC may be involved in formation of pentacyclic triterpenoids.…”
α-Amyrin is a plant-derived pentacyclic triterpenoid, with a lot of important physiological and pharmacological activities. The formation of α-amyrin from (3 S)-2,3-oxidosqualene is catalyzed by α-amyrin synthase (α-AS), a member of the oxidosqualene cyclase (OSC) protein family. However, α-amyrin is not yet commercially developed due to its extremely low productivity in plants. The engineered Saccharomyces cerevisiae with efficient α-amyrin production pathway could be used as an alternative and sustainable solution to produce α-amyrin from renewable raw materials. To efficiently improve α-amyrin production in S. cerevisiae, we identified two α-ASs, EjAS and MdOSC1 from Eriobotrya japonica and Malus × domestica, respectively, through strict bioinformatics screening criteria and phylogenetic analysis. The specific activities of purified EjAS and MdOSC1 were 0.0032 and 0.0293 μmol/min/mg, respectively. EjAS produced α-amyrin and β-amyrin at a ratio of 17:3, MdOSC1 produced α-amyrin, β-amyrin and lupeol at a ratio of 86:13:1, indicating MdOSC1 had significantly higher specific activity and higher ratio of α-amyrin than EjAS. Furthermore, MdOSC1 was introduced into S. cerevisiae combining with the increased supply of (3 S)-2,3-oxidosqualene to achieve the encouraging α-amyrin production, and the titer of α-amyrin achieved 11.97 ± 0.61 mg/L, 5.8 folds of the maximum production reported.
“…Among them, the DCTAE motif might be crucial for the interaction between the protein and its substrate [ 38 ]. The QW repeat is a negatively charged aromatic region that equalizes carbocation in the cyclization reaction, which may play a role in the structural stabilization of proteins [ 39 ]. Fig.…”
Background
Helicteres angustifolia has long been used in Chinese traditional medicine. It has multiple pharmacological benefits, including anti-inflammatory, anti-viral and anti-tumor effects. Its main active chemicals include betulinic acid, oleanolic acid, helicteric acid, helicterilic acid, and other triterpenoid saponins. It is worth noting that some acylated triterpenoids, such as helicteric acid and helicterilic acid, are characteristic components of Helicteres and are relatively rare among other plants. However, reliance on natural plants as the only sources of these is not enough to meet the market requirement. Therefore, the engineering of its metabolic pathway is of high research value for enhancing the production of secondary metabolites. Unfortunately, there are few studies on the biosynthetic pathways of triterpenoids in H. angustifolia, hindering its further investigation.
Results
Here, the RNAs of different groups treated by metabolic stimulation were sequenced with an Illumina high-throughput sequencing platform, resulting in 121 gigabases of data. A total of 424,824 unigenes were obtained after the trimming and assembly of the raw data, and 22,430 unigenes were determined to be differentially expressed. In addition, three oxidosqualene cyclases (OSCs) and four Cytochrome P450 (CYP450s) were screened, of which one OSC (HaOSC1) and one CYP450 (HaCYPi3) achieved functional verification, suggesting that they could catalyze the production of lupeol and oleanolic acid, respectively.
Conclusion
In general, the transcriptomic data of H. angustifolia was first reported and analyzed to study functional genes. Three OSCs, four CYP450s and three acyltransferases were screened out as candidate genes to perform further functional verification, which demonstrated that HaOSC1 and HaCYPi3 encode for lupeol synthase and β-amyrin oxidase, which produce corresponding products of lupeol and oleanolic acid, respectively. Their successful identification revealed pivotal steps in the biosynthesis of acylated triterpenoids precursors, which laid a foundation for further study on acylated triterpenoids. Overall, these results shed light on the regulation of acylated triterpenoids biosynthesis.
“…A fulllength oxidosqualenecyclasec DNA from Bacopa monnieri oxidosqualenecyclases (BmOSC) has been isolated and characterized. Quantitative realtime PCR (qRT-PCR) data showed that BmOSC is expressed in all tissues examined with higher expression in stem and leaves as compared to roots and floral parts 96 . A full-length SQS gene has also been isolated from B. monnieri and characterized as B. monnieri squalene synthase (BmSQS) (1242 bp) encoding 414 amino acids.…”
Section: Analysis Of Metabolic Pathway Gene Expressionmentioning
In recent times, the use of herbal products has increased tremendously in the developing as well as in developed countries. Bacopa monnieri is one of the most important medicinal plant that has been consumed for thousands of year as a memory enhancing, anti-inflammatory, analgesic, antipyretic, sedative and anti-epileptic agent. For many years, a lot of commercial and medicinal researches have been focusing their resources on this plant. The plant has been known to possess various activities such as, antibacterial, anti-fungal, anti-cancer, anti-oxidant, anti-inflammatory, antihyperglycemic, anti-depressant, anti-epileptic, memory enhancer, anti-ulcer, hepatoprotective, analgesic, anti-diarrheal, anti-hypertensive, anti-toxicity etc. Therefore step should be taken for its sustainable use and conservation. This review describes the phytoconstituents, traditional uses, and pharmacological activities of Bacopa monnieri. In brief, the biotechnological applications such as tissue culture, elicitation, genetic transformation for the advancement of this plant and its active components production have also been described. Habitat, Geographical Distribution, and Ethnomedical Description: Bacopa monnieri is a perennial, creeping herb whose habitat includes wetlands and muddy shores. The leaves are succulent, relatively thick, oblanceolate and are
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
