[Modification of C20 oxidase in tanshinone biosynthesis pathway].

Tanshinones are one of the main effective components of Salvia miltiorrhiza, which play important roles in the treatment of cardiovascular diseases. Microbial heterogony production of tanshinones can provide a large number of raw materials for the production of traditional Chinese medicine(TCM) preparations containing S. miltiorrhiza, reduce the extraction cost, and relieve the pressure of clinical medication. The biosynthetic pathway of tanshinones contains multiple P450 enzymes, and the catalytic element with high efficiency is the basis of microbial production of tanshinones. In this study, the protein modification of CYP76AK1, a key P450-C20 hydroxylase in tanshinone pathway, was researched. The protein modeling methods SWISS-MODEL, Robetta, and AlphaFold2 were used, and the protein model was analyzed to obtain the reliable protein structure. The semi-rational design of mutant protein was carried out by molecular docking and homologous alignment. The key amino acid sites affecting the oxidation activity of CYP76AK1 were identified by molecular docking. The function of the obtained mutations was studied with yeast expression system, and the CYP76AK1 mutations with continuous oxidation function to 11-hydroxysugiol were obtained. Four key amino acid sites that affected the oxidation acti-vity were analyzed, and the reliability of three protein modeling methods was analyzed according to the mutation results. The effective protein modification sites of CYP76AK1 were reported for the first time in this study, which provides a catalytic element for different oxidation activities at C20 site for the study of the synthetic biology of tanshinones and lays a foundation for the analysis of the conti-nuous oxidation mechanism of P450-C20 modification.

[Identification of genes involved in biosynthesis of paeoniflorin in Paeonia lactiflora based on transcriptome analysis].

Paeoniflorin, a representative pinane monoterpene glycoside, is the main active component and quality index of Paeoniae Radix Alba and Paeoniae Radix Rubra.The possible biosynthesis of paeoniflorin is as follows: GPP is derived from mevalonate(MVA) and/or 2-C-methyl-D-erythritol 4-phosphate(MEP) pathway(s) followed by the catalysis with terpene synthase, cytochrome P450(CYP450), UDP-glucuronosyltransferase(UGT), and acyltransferase(AT), respectively.This study aims to explore the genes rela-ted to the biosynthesis of paeoniflorin.To be specific, the cDNA libraries for flowers, leaves, and roots of Paeonia lactiflora were established and sequenced.A total of 30 609 open reading frames(ORFs) were yielded.Through functional annotation and expression analysis of all CYP450 genes in the transcriptome, 11 CYP450 genes belonging to CYP71 A and CYP71 D subfamilies and showing expression trend consistent with monoterpene synthase PlPIN that may be involved in paeoniflorin biosynthesis were screened out.Subsequently, 7 UGT genes and 9 AT genes demonstrating the expression trend consistent with PlPIN which were possibly involved in paeoniflorin biosynthesis were further screened by functional annotation analysis, full-length sequence analysis, expression analysis, and phylogeny analysis.This study provided a systematic screening method with smaller number of candidate genes, thus reducing the workload of functional gene verification.The result laid a foundation for analyzing the biosynthesis pathway of paeoniflorin and the formation mechanism.

[Accumulation and biosynthetic of curcuminoids and terpenoids in turmeric rhizome in different development periods].

The dynamic accumulation rule of active substances in medicinal plants is of great value not only for medicinal material production and application,but also for the genetic mechanism study on the formation of medicinal ingredients,especially vital to guide medicinal material collection as well as experiment material selection and candidate gene screening in the analysis of biosynthesis pathway. This study investigated the accumulation of curcumins and terpenoids,and the biosynthesis of these metabolites,which are the active metabolites in Curcuma longa,a commonly used traditional Chinese medicine. Rhizoma of C. longa from leaf growing period,rhizome swelling period and dry matter accumulating period were used as experimental materials,to analyze the changes of metabolites and biosynthesis in the three periods by comparative transcriptome and metabolomes analysis.The results indicated that terpenoids accumulation and biosynthesis mainly occurred in leaf growing period,while curcumin accumulation and biosynthesis mainly occurred in dry matter accumulating period. Therefore,we suggested that turmeric rhizomes in leaf growth period were suitable for terpenoids biosynthetic pathway characterization,and rhizome in accumulation of dry matter period was suitable for curcuminoid biosynthesis pathway characterization. This study provides references for medicinal materialproduction and application,as well as biopathway analysis of active compounds for C. longa.