Modification of C20 oxidase in tanshinone biosynthesis pathway / 中国中药杂志

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.

Advances in research methods for biosynthetic pathway analysis of active ingredients in traditional Chinese medicine / 中国中药杂志

The active ingredients in traditional Chinese medicine(TCM)are the foundation for the efficiency of TCM and the key to the formation of Dao-di herbs. It is of great significance to study the biosynthesis and regulation mechanisms of these active ingredients for analyzing the formation mechanism of Daodi herbs and providing components for the production of active ingredients in TCM by synthetic biology. With the advancements in omics technology, molecular biology, synthetic biology, artificial intelligence, etc., the analysis of biosynthetic pathways for active ingredients in TCM is rapidly progressing. New methods and technologies have promoted the analysis of the synthetic pathways of active ingredients in TCM and have also made this area a hot topic in molecular pharmacognosy. Many researchers have made significant progress in analyzing the biosynthetic pathways of active ingredients in TCM such as Panax ginseng, Salvia miltiorrhiza, Glycyrrhiza uralensis, and Tripterygium wilfordii. This paper systematically reviewed current research me-thods for analyzing the biosynthetic functional genes of active ingredients in TCM, elaborated the mining of gene elements based on multiomics technology and the verification of gene functions in plants in vitro and in vivo with candidate genes as objects. Additionally, the paper summarized new technologies and methods that have emerged in recent years, such as high-throughput screening, molecular probes, genome-wide association studies, cell-free systems, and computer simulation screening to provide a comprehensive reference for the analysis of the biosynthetic pathways of active ingredients in TCM.

Advances on the microbial synthesis of plant-derived diterpenoids / 生物工程学报

Natural plant-derived diterpenoids are a class of compounds with diverse structures and functions. These compounds are widely used in pharmaceuticals, cosmetics and food additives industries because of their pharmacological properties such as anticancer, anti-inflammatory and antibacterial activities. In recent years, with the gradual discovery of functional genes in the biosynthetic pathway of plant-derived diterpenoids and the development of synthetic biotechnology, great efforts have been made to construct a variety of diterpenoid microbial cell factories through metabolic engineering and synthetic biology, resulting in gram-level production of many compounds. This article summarizes the construction of plant-derived diterpenoid microbial cell factories through synthetic biotechnology, followed by introducing the metabolic engineering strategies applied to improve plant-derived diterpenoids production, with the aim to provide a reference for the construction of high-yield plant-derived diterpenoid microbial cell factories and the industrial production of diterpenoids.

Heterologous production of bioactive xenoacremone analogs in Aspergillus nidulans / 中国天然药物

Tyrosine-decahydrofluorene derivatives are a class of hybrid compounds that integrate the properties of polyketides and nonribosomal peptides. These compounds feature a [6.5.6] tricarbocyclic core and a para-cyclophane ether moiety in their structures and exhibit anti-tumor and anti-microbial activities. In this study, we constructed the biosynthetic pathway of xenoacremones from Xenoacremonium sinensis ML-31 in the Aspergillus nidulans host, resulting in the identification of four novel tyrosine-decahydrofluorene analogs, xenoacremones I-L (1-4), along with two known analogs, xenoacremones A and B. Remarkably, compounds 3 and 4 contained a 12-membered para-cyclophane ring system, which is unprecedented among tyrosine-decahydrofluorene analogs in X. sinensis. The successful reconstruction of the biosynthetic pathway and the discovery of novel analogs demonstrate the utility of heterologous expression strategy for the generation of structurally diverse natural products with potential biological activities.

Graph-based and constraint-based heterologous metabolic pathway design methods and application / 生物工程学报

It is among the goals in metabolic engineering to construct microbial cell factories producing high-yield and high value-added target products, and an important solution is to design efficient synthetic pathway for the target products. However, due to the difference in metabolic capacity among microbial chassises, the available substrate and the yielded products are limited. Therefore, it is urgent to design related metabolic pathways to improve the production capacity. Existing metabolic engineering approaches to designing heterologous pathways are mainly based on biological experience, which are inefficient. Moreover, the yielded results are in no way comprehensive. However, systems biology provides new methods for heterologous pathway design, particularly the graph-based and constraint-based methods. Based on the databases containing rich metabolism information, they search for and uncover possible metabolic pathways with designated strategy (graph-based method) or algorithm (constraint-based method) and then screen out the optimal pathway to guide the modification of strains. In this paper, we reviewed the databases and algorithms for pathway design, and the applications in metabolic engineering and discussed the strengths and weaknesses of existing algorithms in practical application, hoping to provide a reference for the selection of optimal methods for the design of product synthesis pathway.

Construction and application of microbial cell factories for unnatural amino acids / 生物工程学报

Unnatural amino acids are widely used in medicine, pesticide, material, and other industries and the green and efficient synthesis has attracted a lot of attention. In recent years, with the rapid development of synthetic biology, microbial cell factories have become a promising means for biosynthesis of unnatural amino acids. This study reviewed the construction and application of microbial cell factories for unnatural amino acid, including the synthetic pathway reconstruction, design/modification of key enzymes and their coordinated regulation with precursors, blocking of competitive alternative pathways, and construction of cofactor circulation systems. Meanwhile, on the basis of the new principles for designing the microbial cell factories, new biosynthetic pathways adapted to cells and the production environment, as well as new biomanufacturing system established based on cell adaptive evolution and intelligent fermentation regulation, we looked forward to the further construction and application of microbial cell factories for industrial bio-production.

Effect of key enzymes ubiquitination sites on the biosynthesis of naringenin / 生物工程学报

Flavonoids have a variety of biological activities and have important applications in food, medicine, cosmetics, and many other fields. Naringenin is a platform chemical for the biosynthesis of many important flavonoids. Ubiquitination plays a pivotal role in the post-translational modification of proteins and participates in the regulation of cellular activities. Ubiquitinated proteins can be degraded by the ubiquitin-protease system, which is important for maintaining the physiological activities of cells, and may also exert a significant impact on the expression of exogenous proteins. In this study, a real-time in-situ detection system for ubiquitination modification has been established in Saccharomyces cerevisiae by using a fluorescence bimolecular complementation approach. The ubiquitination level of protein was characterized by fluorescence intensity. By using the approach, the potential ubiquitination sites of proteins involved in the naringenin biosynthesis pathway have been obtained. The lysine residues of the relevant ubiquitination sites were mutated to arginine to reduce the ubiquitination level. The mutants of tyrosine ammonia-lyase (FjTAL) and chalcone synthase (SjCHS, SmCHS) showed decreased fluorescence, suggested that a decreased ubiquitination level. After fermentation verification, the S. cerevisiae expressing tyrosine ammonia-lyase FjTAL mutant FjTAL-K487R accumulated 74.2 mg/L p-coumaric acid at 72 h, which was 32.3% higher than that of the original FjTAL. The strains expressing chalcone synthase mutants showed no significant change in the titer of naringenin. The results showed that mutation of the potential ubiquitination sites of proteins involved in the naringenin biosynthesis pathway could increase the titer of p-coumaric acid and have positive effect on naringenin biosynthesis.

Microbial synthesis of monoterpenoids: a review / 生物工程学报

Monoterpenoids that belong to the terpenoids family are usually volatile and have strong aroma. Some monoterpenoids also have antioxidant, antibacterial and anti-inflammatory activities, which make them important raw materials for medicine, food and cosmetics industry. In recent years, the heterologous synthesis of monoterpenoids by microorganisms has attracted extensive attention. However, its large-scale application is greatly hampered by the low yield and high production cost. Nowadays, the rapid development of synthetic biology provides new approaches for enhancing the production of monoterpenoids by microorganisms. Different kinds of recombinant strains can be obtained via engineering of microbial cells to produce a variety of monoterpenoids with different properties. This paper summarized the latest strategies and progress in the application of synthetic biology to produce monoterpenoids by microorganisms, including the design and modification of biosynthetic pathway, as well as the design and optimization of high-yield monoterpenoids producing chassis cells.

Microbes as a production host to produce natural activecompounds from mushrooms: biosynthetic pathway elucidationand metabolic engineering / 中国天然药物

Mushrooms are abundant in bioactive natural compounds. Due to strict growth conditions and long fermentation-time, microbe as a production host is an alternative and sustainable approach for the production of natural compounds. This review focuses on the biosynthetic pathways of mushroom originated natural compounds and microbes as the production host for the production of the above natural compounds.

Germacrene-derived sesquiterpene lactones:opportunities and challenges for biosynthesis / 中国中药杂志

Sesquiterpene lactones are a kind of widely distributed natural organic compounds with anti-tumor, anti-malarial and other significant biological activities. Based on their carbocylic skeletons, sesquiterpene lactones are classified into germacranolide, guaia-nolide, xanthanolide, pseudo-guaianolide, elemonolide and eudesmanolide, etc. In recent years, with the development of various omics and synthetic biology technologies, the biosynthetic pathways of sesquiterpene lactone compounds of different structural types have gradually been resolved. Among them, the researches on germacrene-derived sesquiterpene lactones are relatively more than others. Therefore, this article focused on the germacrene-derived sesquiterpene lactone biosynthesis pathways and their key enzyme genes, which can lay the foundation for in-depth analysis of sesquiterpene lactone biosynthetic pathways, functional gene mining and heterologous synthesis of active ingredients.

Identification of potential genes involved in biosynthesis of flavonoid and analysis of biosynthetic pathway in Fagopyrum dibotrys / 中国中药杂志

In order to enrich the transcriptome data of Fagopyrum dibotrys plants, analyze the genes encoding key enzyme involved in flavonoid biosynthesis pathway, and mine their functional genes, in this study, we performed RNA sequencing analysis for the rhizomes, roots, flowers, leaves and stems of F. dibotrys on the BGISEQ-500 sequencing platform. After de novo assembly of transcripts, a total of 205 619 unigenes were generated and 132 372 unigenes were obtained and annotated into seven public databases, of which, 81 327 unigenes were mapped to the GO database and most of the unigenes were annotated in cellular process, biological regulation, binding and catalytic activity. Besides, 86 922 unigenes were enriched in 136 pathways using KEGG database' and we identified 82 unigenes that encodes key enzymes involved in flavonoid biosynthesis. Comparing rhizome with root, flower, leaf or stem in F. dibotrys, 27 962 co-expressed differentially expressed genes(DEGs) were obtained. Among them, 23 515 DEGs of rhizome tissue-specific were enriched into 132 pathways and 13 unigenes were significantly enriched in biosynthesis of flavone and flavonol. In addition, we also identified 3 427 unigenes encoding 60 transcription factor(TFs) families as well as four unigenes encoding bHLH TFs were enriched in flavonoid biosynthesis. Our results greatly enriched the transcriptome database of plants, provided a reference for the analysis of key enzymes involved in flavonoid biosynthesis in plants, and will facilitate the study of the functions and regulatory mechanisms of key enzymes involved in flavonoid biosynthesis in F. dibotrys at the genetic level.

Advances in metabolic engineering for the production of aromatic chemicals / 生物工程学报

Metabolic engineering has been developed for nearly 30 years since the early 1990s, and it has given a great impetus to microbial strain breeding and improvement. Aromatic chemicals are a variety of important chemicals that can be produced by microbial fermentation and are widely used in the pharmaceutical, food, feed, and material industry. Microbial cells can be engineered to accumulate a variety of useful aromatic chemicals in a targeted manner through rational engineering of the biosynthetic pathways of shikimate and the derived aromatic amino acids. This review summarizes the metabolic engineering strategies and biosynthetic pathways for the production of aromatic chemicals developed in the past 30 years, with the aim to provide a valuable reference and promote the research in this field.

Microbial green manufacturing of higher alcohols / 生物工程学报

Higher alcohols that contain more than two carbon atoms have better fuel properties than ethanol, making them important supplements and alternatives to fossil fuels. Using microbes to produce higher alcohols from renewable biomass can alleviate the current energy and environmental crises, and has become a major future direction for green biomanufacturing. Since natural microbes can only produce a few higher alcohols in small amounts, it is necessary to reconstruct the synthetic pathways for higher alcohols in model industrial strains through metabolic engineering and synthetic biology to overcome the metabolic bottlenecks. A series of milestones have been accomplished in past decades. The authors of this review have witnessed the entire journey of this field from its first success to the leaping development. On the 30th anniversary of the founding of the discipline of metabolic engineering, this review dates back to the great milestones in achieving heterologous production of higher alcohols in non-native strains. The design and optimization of high alcohol biosynthetic pathways, the expansion of feedstock, the engineering of host strains and the industrialization process are summarized. This review aims to draw further attention to microbial synthesis of higher alcohols, inspire the development of novel techniques and strategies of metabolic engineering, and promote the innovation and upgrade of China's biofuel industry.

Advances in the metabolic engineering for the production of tetracarbon organic acids / 生物工程学报

Tetracarbon organic acids are important platform chemicals that are widely used in the food, chemical, medicine, material industries and agriculture. Compared with the traditional petrochemical process, the production of tetracarbon organic acids by microbial fermentation is more promising due to milder reaction conditions, greener process and better environmental compatibility. This review summarizes the biosynthetic pathways and metabolic mechanisms for the production of tetracarbon organic acids, and illustrates recent advances, challenges, and future perspectives in the production of tetracarbon organic acids by naturally selected or purposefully engineered strains.

Pathway design and key enzyme analysis of diosgenin biosynthesis / 生物工程学报

As a naturally occurring steroid sapogenin, diosgenin acts as the precursor of hundreds of steroid medicines, and thereby has important medicinal value. Currently, industrial production of diosgenin relies primarily on chemical extraction from plant materials. Clearly, this strategy shows drawbacks of excessive reliance on plant materials and farmland as well as environment pollution. Due to development of metabolic engineering and synthetic biology, bio-production of diosgenin has garnered plenty of attention. Although the biosynthetic pathways of diosgenin have not been completely identified, in this review, we outline the identified biosynthetic pathways and key enzymes. In particular, we suggest heterologous biosynthesis of diosgenin in Saccharomyces cerevisiae. Overall, this review aims to provide valuable insights for future complete biosynthesis of diosgenin.

Research progresses in the biosynthesis of curcuminoids / 生物工程学报

Curcuminoids are rare diketone compounds in plants and can be found in the rhizome of Curcuma longa as well as other Zingiberaceae and Araceae. Curcuminoids have been widely used in food and medical area owing to the yellow colors, as well as the antioxidant and many other pharmacological activities. Curcuminoids are a mixture of compounds containing curcumin, demethoxycurcumin and bisdemethoxycurcumin, which have distinct benzene ring substituents. Currently, curcuminoids are exclusively produced through plant extraction, which do not satisfy the meeting of the market demand. Empowered with new synthetic biology tools and metabolic engineering strategies, there is renewed interest in production of curcuminoids using microorganisms. Heterologous production of curcuminoids has been achieved using Escherichia coli, Yarrowia lipolytica, Pseudomonas putida and Aspergillus oryzae via engineering of curcuminoids biosynthesis pathway. In this review, we first describe the biological activities and various applications of curcuminoids. Next, we summarize the biosynthetic pathway of curcuminoids in Curcuma longa and discuss the catalytic mechanisms of curcumin synthases. Then, we thoroughly explore recent advances in the use of distinct microorganisms for the production of curcuminoids with a special focus on metabolic engineering strategies. Finally, we prospect the microbial production of curcuminoids by highlighting some promising techniques and approaches.

A preliminary pharmacophylogenetic study of Solanaceae medicinal plants containing tropane alkaloids / 中国中药杂志

The Solanaceae plants distributed in China belong to 105 species and 35 varietas of 24 genera. Some medicinal plants of Solanaceae are rich in tropane alkaloids(TAs), which have significant pharmacological activities. In this paper, the geographical distribution, chemical components, traditional therapeutic effect, pharmacological activities, and biosynthetic pathways of TAs in Solanaceous plants were summarized. Besides, the phylogeny of medicinal plants belonging to Solanaceae was visualized by network diagram. Fourteen genera of Solanaceae plants in China contain TAs and have medical records. TAs mainly exist in Datura, Anisodus, Atropa, Physochlaina, and Hyoscyamus. The TAs-containing species were mainly concentrated in Southwest China, and the content of TAs was closely related to plant distribution area and altitude. The Solanaceae plants containing TAs mainly have antispasmodic, analgesic, antiasthmatic, and antitussive effects. Modern pharmacological studies have proved the central sedative, pupil dilating, glandular secretion-inhibiting, and anti-asthma activities of TAs. These pharmacological activities provide a reasonable explanation for the traditional therapeutic efficacy of tropane drugs. In this paper, the geographical distribution, chemical components, traditional therapeutic effect, and modern pharmacological activities of TAs-containing species in Solanaceae were analyzed for the first time. Based on these data, the genetic relationship of TAs-containing Solanaceae species was preliminarily discussed, which provided a scientific basis for the basic research on TAs-containing solanaceous species and was of great significance for the development of natural medicinal plant resources containing TAs.

Effects of water regulation on biosynthesis of calycosin-7-O-β-D-glucoside in Astragalus membranaceus var. mongholicus / 中国中药杂志

The effects of water regulation on the biosynthesis of calycosin-7-O-β-D-glucoside in 2-year-old Astragalus membranaceus var. mongholicus were studied,and the mechanism was explained from the aspects of key enzyme gene expression and antioxidant enzyme system. The content of calycosin-7-O-β-D-glucoside was determined by HPLC,and the expression levels of six key enzyme genes( PAL,4 CL,CHS,CHI,IFS,13'H) in the synthesis pathway were analyzed by q RT-PCR. The activities of protective enzymes and contents of osmoregulation substances and malondialdehyde were also determined. In the water deficit group,the maximum concentration of calycosin-7-O-β-D-glucoside was 0. 49 mg·g-1 on the 24 th day of treatment. In the whole water regulation,the water deficit group outweighed the water adequate group in osmoregulation substance and MDA contents. The activities of A. membranaceus var.mongholicus antioxidant enzymes SOD,POD,and CAT increased during the initial period of water regulation,but decreased with time.The expression of PAL,CHS,and 13'H in the water deficit group was at a low level,and the 4 CL had active expression,slightly lower than that in the water adequate group. The expression of CHI and IFS elevated rapidly when water deficit occurred. Correlation analysis showed that the content of calycosin-7-O-β-D-glucoside was positively correlated with CHI expression( P<0. 01) and IFS expression( P<0. 05). Therefore,water regulation can change the accumulation pattern of calycosin-7-O-β-D-glucoside,and water deficit may be an effective way to increase its content. CHI and IFS are the key genes in response to water deficit.

Advances in metabolic engineering of Saccharomyces cerevisiae for terpenoids biosynthesis / 生物工程学报

Terpenoids are a group of structurally diverse compounds with good biological activities and versatile functions such as anti-cancer and immunity-enhancing effects, and are widely used in food, healthcare and medical industries. Facilitated by the increasing understandings on the natural biosynthetic pathways of terpenoids in recent years, Saccharomyces cerevisiae has been engineered into high-yield strains for production of a variety of terpenoids, some of which have reached or become close to the level required by industrial production. In this connection, synthetic biology driven biotechnological production of terpenoids has become a promising alternative to chemical synthesis and traditional extraction approaches. This article summarizes the recent process in engineering S. cerevisiae for terpenoids biosynthesis, highlighting the effect of synthetic biology strategies by taking a couple of typical terpenoids as examples.

Microbial synthesis of plant polyphenols / 生物工程学报

Plant polyphenols are phenylpropanoid derivatives including phenolic acids, stilbenes, curcumins and flavonoids. These compounds display a variety of biological and pharmacological activities such as antioxidation, vasorelaxation, anti-coagulation, anti-inflammation, anti-tumor and anti-virus, conferring a huge application potential in the sectors of drugs, foods, cosmetics, and chemicals. Microorganisms have become important hosts for heterologous synthesis of natural products due to the advantages of fast growth, easiness of culture and industrial operation. In recent years, the development of synthetic biology has boosted the microbial synthesis of plant natural products, achieving substantial progress. In this review, we summarize the synthesis of plant polyphenols in engineered Escherichia coli, Saccharomyces cerevisiae and other microorganisms equipped with the designed biosynthetic pathways of polyphenols. We also discuss the optimization strategies such as precursor engineering, dynamic regulation, and co-cultivation to improve the production of polyphenols and propose future prospects for polyphenol pathway engineering.