Several 14 alpha- and 14 beta -bromo baccatin III derivatives were synthesized by direct bromination and from silyl enol ether of 13-oxo-7-TES-baccatin III. 14 beta -Hyroxy baccatin III derivative was also obtained fr...Several 14 alpha- and 14 beta -bromo baccatin III derivatives were synthesized by direct bromination and from silyl enol ether of 13-oxo-7-TES-baccatin III. 14 beta -Hyroxy baccatin III derivative was also obtained from the same silyl enol ether.展开更多
1-Hydroxyl acetylation of 10-deacetylbaccatin Ⅲ was achieved by removing the neighboring bulky 2-benzoyl group and oxidizing 2-hydroxyl group to a ketone function, but attempted reductive cleavage of 1-acetoxy gave r...1-Hydroxyl acetylation of 10-deacetylbaccatin Ⅲ was achieved by removing the neighboring bulky 2-benzoyl group and oxidizing 2-hydroxyl group to a ketone function, but attempted reductive cleavage of 1-acetoxy gave rearranged products under different conditions with or without proton source.展开更多
The characterization and reconstitution of Taxus enzymes leading to taxoids (diterpenoids with the taxane skeleton seen in the taxol molecule)[1–5] are exciting and may tempt researchers to update the episode about t...The characterization and reconstitution of Taxus enzymes leading to taxoids (diterpenoids with the taxane skeleton seen in the taxol molecule)[1–5] are exciting and may tempt researchers to update the episode about taxol that has been, and will be, prescribed to combat diverse cancers.展开更多
Paclitaxel,a tetracyclic diterpenoid,has garnered attention for its potent anti-cancer properties and intricate molecular structure,making it a significant target for chemical synthesis and biosynthesis[1].However,its...Paclitaxel,a tetracyclic diterpenoid,has garnered attention for its potent anti-cancer properties and intricate molecular structure,making it a significant target for chemical synthesis and biosynthesis[1].However,its natural sources are extremely limited,as it is derived exclusively from the bark of endangered genus Taxus plants,which contain paclitaxel in very low concentrations(0.01%−0.05%)[2-3].Recent advances in synthetic biology present promising opportunities to enhance paclitaxel levels in Taxus cell cultures or to enable the reconstitution of its production in heterologous hosts,such as yeast or tobacco(Nicotiana benthamiana).展开更多
10-DeacetylbaccatinⅢ(10-DAB)C10 acetylation is an indispensable procedure for Taxol semi-synthesis,which often requires harsh conditions.10-DeacetylbaccatinⅢ-10-β-O-acetyltransferase(DBAT)catalyzes the acetylation ...10-DeacetylbaccatinⅢ(10-DAB)C10 acetylation is an indispensable procedure for Taxol semi-synthesis,which often requires harsh conditions.10-DeacetylbaccatinⅢ-10-β-O-acetyltransferase(DBAT)catalyzes the acetylation but acetyl-CoA supply remains a key limiting factor.Here we refactored the innate biosynthetic pathway of acetyl-CoA in Escherichia coli and obtained a chassis with acetyl-CoA productivity over three times higher than that of the host cell.Then,we constructed a microbial cell factory by introducing DBAT gene into this chassis for efficiently converting 10-DAB into baccatinⅢ.We found that baccatinⅢcould be efficiently deacetylated into 10-DAB by DBAT with CoASH and K+under alkaline condition.Thus,we fed acetic acid to the engineered strain both for serving as a substrate of acetyl-CoA biosynthesis and for alleviating the deacetylation of baccatinⅢ.The fermentation conditions were optimized and the baccatinⅢtiters reached 2,3 and 4.6 g/L,respectively,in a 3-L bioreactor culture when 2,3 and 6 g/L of 10-DAB were supplied.Our study provides an environmentfriendly approach for the large scale 10-DAB acetylation without addition of acetyl-CoA in the industrial Taxol semi-synthesis.The finding of DBAT deacetylase activity may broaden its application in the structural modification of pharmaceutically important lead compounds.展开更多
As baccatin Ⅲ is an immediate diterpenoid precursor of taxol, the increase of baccatin Ⅲ is beneficial to the biosynthesis of taxol. Addition of methyl jasmonic acid （M J） enhances the activity of 10- deaceyle bac...As baccatin Ⅲ is an immediate diterpenoid precursor of taxol, the increase of baccatin Ⅲ is beneficial to the biosynthesis of taxol. Addition of methyl jasmonic acid （M J） enhances the activity of 10- deaceyle baccatin （DAB） iii acetyl transferase which catalyzes the bioconversion from 10-DAB Ⅲ to beccatin Ⅲ. In this paper, the baccatin Ⅲ content was increased by 174% by the addition of 100 IJmol/L MJ in suspension cultures of Taxus cuspidate. Induction by MJ also increased the expression of a 49.0-kDa protein. This paper describes the cell free acetylation of 10-DAB Ⅲ in crude extracts of enzyme from the suspension cultures of Taxus cuspidate. The reaction product was confirmed by high performance liquid chromatograph （HPLC）. About 25.0% of the 10-DAB Ⅲ was acetylized into baccatin Ⅲ on the 4th day with 100 IJmol/L MJ. The 10-DAB Ⅲ acetyl transferase activity reached a peak on the 2nd day with 100 μmol/L MJ, with 54.7% of the 10-DAB Ⅲ transformed into baccatin Ⅲ. The baccatin Ⅲ content increased with the increase of 10-DAB Ⅲ acetyl transferase activity, although the biosynthesis was delayed by more than 24 h. The remarkable induction of MJ on baccatin Ⅲ biosynthesis shows a promising way to increase the production of taxol.展开更多
Two new baccatin Ⅲ type taxoids, 13-Cinnamoylbaccatin Ⅲ (1) and 7-xylosylbaccatin Ⅲ(2), have been isolated from the barks of Taxus yunnanensis. The structures were elucidated by spectral means.
文摘Several 14 alpha- and 14 beta -bromo baccatin III derivatives were synthesized by direct bromination and from silyl enol ether of 13-oxo-7-TES-baccatin III. 14 beta -Hyroxy baccatin III derivative was also obtained from the same silyl enol ether.
文摘1-Hydroxyl acetylation of 10-deacetylbaccatin Ⅲ was achieved by removing the neighboring bulky 2-benzoyl group and oxidizing 2-hydroxyl group to a ketone function, but attempted reductive cleavage of 1-acetoxy gave rearranged products under different conditions with or without proton source.
基金supported by the National Natural Science Foundation of China (81991524, 32388201)Yunnan Revitalization Talent Support Program Project (202305AT350001)。
文摘The characterization and reconstitution of Taxus enzymes leading to taxoids (diterpenoids with the taxane skeleton seen in the taxol molecule)[1–5] are exciting and may tempt researchers to update the episode about taxol that has been, and will be, prescribed to combat diverse cancers.
文摘Paclitaxel,a tetracyclic diterpenoid,has garnered attention for its potent anti-cancer properties and intricate molecular structure,making it a significant target for chemical synthesis and biosynthesis[1].However,its natural sources are extremely limited,as it is derived exclusively from the bark of endangered genus Taxus plants,which contain paclitaxel in very low concentrations(0.01%−0.05%)[2-3].Recent advances in synthetic biology present promising opportunities to enhance paclitaxel levels in Taxus cell cultures or to enable the reconstitution of its production in heterologous hosts,such as yeast or tobacco(Nicotiana benthamiana).
基金supported by the National Key Research and Development Program of China(grant Nos.2018YFA0901900 and 2020YFA0908003)the Drug Innovation Major Project(grant No.2018ZX09711001-006-001,China)+2 种基金the National Natural Science Foundation of China(grant No.81573325)the CAMS Innovation Fund for Medical Sciences(CIFMS,(grant No.2017-I2M-2-004,2019-I2M-1-005,China)PUMC Disciplinary Development of Synthetic Biology(201920100801,China)。
文摘10-DeacetylbaccatinⅢ(10-DAB)C10 acetylation is an indispensable procedure for Taxol semi-synthesis,which often requires harsh conditions.10-DeacetylbaccatinⅢ-10-β-O-acetyltransferase(DBAT)catalyzes the acetylation but acetyl-CoA supply remains a key limiting factor.Here we refactored the innate biosynthetic pathway of acetyl-CoA in Escherichia coli and obtained a chassis with acetyl-CoA productivity over three times higher than that of the host cell.Then,we constructed a microbial cell factory by introducing DBAT gene into this chassis for efficiently converting 10-DAB into baccatinⅢ.We found that baccatinⅢcould be efficiently deacetylated into 10-DAB by DBAT with CoASH and K+under alkaline condition.Thus,we fed acetic acid to the engineered strain both for serving as a substrate of acetyl-CoA biosynthesis and for alleviating the deacetylation of baccatinⅢ.The fermentation conditions were optimized and the baccatinⅢtiters reached 2,3 and 4.6 g/L,respectively,in a 3-L bioreactor culture when 2,3 and 6 g/L of 10-DAB were supplied.Our study provides an environmentfriendly approach for the large scale 10-DAB acetylation without addition of acetyl-CoA in the industrial Taxol semi-synthesis.The finding of DBAT deacetylase activity may broaden its application in the structural modification of pharmaceutically important lead compounds.
文摘As baccatin Ⅲ is an immediate diterpenoid precursor of taxol, the increase of baccatin Ⅲ is beneficial to the biosynthesis of taxol. Addition of methyl jasmonic acid （M J） enhances the activity of 10- deaceyle baccatin （DAB） iii acetyl transferase which catalyzes the bioconversion from 10-DAB Ⅲ to beccatin Ⅲ. In this paper, the baccatin Ⅲ content was increased by 174% by the addition of 100 IJmol/L MJ in suspension cultures of Taxus cuspidate. Induction by MJ also increased the expression of a 49.0-kDa protein. This paper describes the cell free acetylation of 10-DAB Ⅲ in crude extracts of enzyme from the suspension cultures of Taxus cuspidate. The reaction product was confirmed by high performance liquid chromatograph （HPLC）. About 25.0% of the 10-DAB Ⅲ was acetylized into baccatin Ⅲ on the 4th day with 100 IJmol/L MJ. The 10-DAB Ⅲ acetyl transferase activity reached a peak on the 2nd day with 100 μmol/L MJ, with 54.7% of the 10-DAB Ⅲ transformed into baccatin Ⅲ. The baccatin Ⅲ content increased with the increase of 10-DAB Ⅲ acetyl transferase activity, although the biosynthesis was delayed by more than 24 h. The remarkable induction of MJ on baccatin Ⅲ biosynthesis shows a promising way to increase the production of taxol.
文摘Two new baccatin Ⅲ type taxoids, 13-Cinnamoylbaccatin Ⅲ (1) and 7-xylosylbaccatin Ⅲ(2), have been isolated from the barks of Taxus yunnanensis. The structures were elucidated by spectral means.
基金ProjectsupportedbythefinancialsupportfromtheStateKeyLaboratoryofPhytochemistryandPlantResourcesinWestChi na ,KunmingInstituteofBotany ,ChineseAcademyofSciences,andsupportedbytheKnowledgeInnovationProjectfromtheNorthWestPlateatInstituteofBiology ,C
