The insufficient supply of sugar units is the key limitation for the biosynthesis of glycosylated products.The unusual sugar TDP-L-mycarose is initially attached to the C3 of the polyketide erythronolide B,resulting i...The insufficient supply of sugar units is the key limitation for the biosynthesis of glycosylated products.The unusual sugar TDP-L-mycarose is initially attached to the C3 of the polyketide erythronolide B,resulting in 3-O-α-mycarosylerythronolide B(MEB).Here,we present the de novo biosynthesis of MEB in Escherichia coli and improve its production using multi-strategy metabolic engineering.Firstly,by blocking precursor glucose-1-phosphate competing pathways,the MEB titer of triple knockout strain QC13 was significantly enhanced to 41.2 mg/L,9.8-fold to that produced by parental strain BAP230.Subsequently,the MEB production was further increased to 48.3 mg/L through overexpression of rfbA and rfbB.Moreover,the CRISPRi was implemented to promote the TDP-L-mycarose biosynthesis via repressing the glycolysis and TDP-L-rhamnose pathway.Our study paves the way for efficient production of erythromycins in E.coli and provides a promising platform that can be applied for biosynthesis of other glycosylated products with unusual sugars.展开更多
杨梅素是一种主要用于抗炎的多酚类黄酮化合物,为改善其水溶性和稳定性,合成了杨梅素-3-O-β-D-乳糖,并开发了一条高效的合成路线。首先以杨梅苷为起始原料,对杨梅苷的5位、7位、3′位、4′位和5′位酚羟基进行保护,形成五苄基保护的杨...杨梅素是一种主要用于抗炎的多酚类黄酮化合物,为改善其水溶性和稳定性,合成了杨梅素-3-O-β-D-乳糖,并开发了一条高效的合成路线。首先以杨梅苷为起始原料,对杨梅苷的5位、7位、3′位、4′位和5′位酚羟基进行保护,形成五苄基保护的杨梅苷。然后脱除3位鼠李糖,再与乙酰基保护的乳糖溴苷反应,最后通过依次脱去乙酰基和苄基得到目标化合物。经过路径优化,最终以更高效的方法合成了杨梅素-3-O-β-D-乳糖,减少了副产物的生成,提高了原合成路线总收率,此方法的总产率为44.5%。该路径得到了2个新型的杨梅素衍生物中间体。目标化合物的结构均经过1 H NMR,13 C NMR和HR-MS(ESI)确证。展开更多
目的建立复方鲜竹沥液中南烛木树脂酚-3α-O-β-d-葡萄糖苷含量的测定方法。方法采用HPLC法,以资生堂capcell pak C_(18)(250mm×4.6mm×5μm)为色谱柱,柱温30℃,乙腈-0.1%磷酸梯度洗脱,流速为1.0mL·min^(-1),检测波长为22...目的建立复方鲜竹沥液中南烛木树脂酚-3α-O-β-d-葡萄糖苷含量的测定方法。方法采用HPLC法,以资生堂capcell pak C_(18)(250mm×4.6mm×5μm)为色谱柱,柱温30℃,乙腈-0.1%磷酸梯度洗脱,流速为1.0mL·min^(-1),检测波长为220nm。结果南烛木树脂酚-3α-O-β-d-葡萄糖苷在0.2264~11.32μg·mL^(-1)浓度范围内线性良好(R^(2)=0.9999),加标回收率为97.06%,RSD(n=9)为1.08%,且方法的精密度、稳定性以及重复性的RSD均小于3.0%。结论该方法快速、简便、准确,可为复方鲜竹沥液的质量控制和评价提供依据。展开更多
目的:研究自兴安升麻提取的23-O-乙酰升麻醇-3-O-β-D-木糖苷对HepG2细胞的细胞毒性及其作用机制。方法:利用MTT法进行细胞毒活性测定;用AO/EB染色法观察细胞个体的凋亡;以流式细胞光度术研究细胞周期的改变并验证凋亡的产生;用蛋白印...目的:研究自兴安升麻提取的23-O-乙酰升麻醇-3-O-β-D-木糖苷对HepG2细胞的细胞毒性及其作用机制。方法:利用MTT法进行细胞毒活性测定;用AO/EB染色法观察细胞个体的凋亡;以流式细胞光度术研究细胞周期的改变并验证凋亡的产生;用蛋白印迹技术从分子水平阐明该化合物的细胞毒作用机制。结果:23-O-乙酰升麻醇-3-O--βD-木糖苷可以明显抑制HepG2细胞生长,IC50为16μmol.L-1。同时该化合物可以使HepG2细胞产生凋亡形态学变化和G2-M细胞周期阻滞,并使PARP蛋白裂解,bc l-2,Bax,cdc 2和cyc lin B等凋亡和细胞周期相关蛋白表达改变。结论:23-O-乙酰升麻醇-3-O--βD-木糖苷对HepG2细胞具有明显的细胞毒作用,该化合物可诱导HepG2细胞凋亡和G2-M周期阻滞,其凋亡机制涉及caspases家族激活,bc l-2和Bax表达改变,而G2-M周期阻滞与cdc 2和cyc lin B下调直接相关。展开更多
基金This study was financially supported by the National Key R&D Program of China(2018YFA0900600)the Program of Shanghai Academic Research Leader(20XD1404400)+4 种基金the Strategic Priority Research Program“Molecular mechanism of Plant Growth and Development”of CAS(XDB27020202)the National Natural Science Foundation of China(31670099)the Construction of the Registry and Database of Bioparts for Synthetic Biology of the Chinese Academy of Science(No.ZSYS-016)the International Partnership Program of Chinese Academy of Science(No.153D31KYSB20170121)the National Key Laboratory of Plant Molecular Genetics,SIPPE,CAS.
文摘The insufficient supply of sugar units is the key limitation for the biosynthesis of glycosylated products.The unusual sugar TDP-L-mycarose is initially attached to the C3 of the polyketide erythronolide B,resulting in 3-O-α-mycarosylerythronolide B(MEB).Here,we present the de novo biosynthesis of MEB in Escherichia coli and improve its production using multi-strategy metabolic engineering.Firstly,by blocking precursor glucose-1-phosphate competing pathways,the MEB titer of triple knockout strain QC13 was significantly enhanced to 41.2 mg/L,9.8-fold to that produced by parental strain BAP230.Subsequently,the MEB production was further increased to 48.3 mg/L through overexpression of rfbA and rfbB.Moreover,the CRISPRi was implemented to promote the TDP-L-mycarose biosynthesis via repressing the glycolysis and TDP-L-rhamnose pathway.Our study paves the way for efficient production of erythromycins in E.coli and provides a promising platform that can be applied for biosynthesis of other glycosylated products with unusual sugars.
文摘杨梅素是一种主要用于抗炎的多酚类黄酮化合物,为改善其水溶性和稳定性,合成了杨梅素-3-O-β-D-乳糖,并开发了一条高效的合成路线。首先以杨梅苷为起始原料,对杨梅苷的5位、7位、3′位、4′位和5′位酚羟基进行保护,形成五苄基保护的杨梅苷。然后脱除3位鼠李糖,再与乙酰基保护的乳糖溴苷反应,最后通过依次脱去乙酰基和苄基得到目标化合物。经过路径优化,最终以更高效的方法合成了杨梅素-3-O-β-D-乳糖,减少了副产物的生成,提高了原合成路线总收率,此方法的总产率为44.5%。该路径得到了2个新型的杨梅素衍生物中间体。目标化合物的结构均经过1 H NMR,13 C NMR和HR-MS(ESI)确证。
文摘目的建立复方鲜竹沥液中南烛木树脂酚-3α-O-β-d-葡萄糖苷含量的测定方法。方法采用HPLC法,以资生堂capcell pak C_(18)(250mm×4.6mm×5μm)为色谱柱,柱温30℃,乙腈-0.1%磷酸梯度洗脱,流速为1.0mL·min^(-1),检测波长为220nm。结果南烛木树脂酚-3α-O-β-d-葡萄糖苷在0.2264~11.32μg·mL^(-1)浓度范围内线性良好(R^(2)=0.9999),加标回收率为97.06%,RSD(n=9)为1.08%,且方法的精密度、稳定性以及重复性的RSD均小于3.0%。结论该方法快速、简便、准确,可为复方鲜竹沥液的质量控制和评价提供依据。
文摘目的:研究自兴安升麻提取的23-O-乙酰升麻醇-3-O-β-D-木糖苷对HepG2细胞的细胞毒性及其作用机制。方法:利用MTT法进行细胞毒活性测定;用AO/EB染色法观察细胞个体的凋亡;以流式细胞光度术研究细胞周期的改变并验证凋亡的产生;用蛋白印迹技术从分子水平阐明该化合物的细胞毒作用机制。结果:23-O-乙酰升麻醇-3-O--βD-木糖苷可以明显抑制HepG2细胞生长,IC50为16μmol.L-1。同时该化合物可以使HepG2细胞产生凋亡形态学变化和G2-M细胞周期阻滞,并使PARP蛋白裂解,bc l-2,Bax,cdc 2和cyc lin B等凋亡和细胞周期相关蛋白表达改变。结论:23-O-乙酰升麻醇-3-O--βD-木糖苷对HepG2细胞具有明显的细胞毒作用,该化合物可诱导HepG2细胞凋亡和G2-M周期阻滞,其凋亡机制涉及caspases家族激活,bc l-2和Bax表达改变,而G2-M周期阻滞与cdc 2和cyc lin B下调直接相关。
