Sugar aminotransferases(SATs)catalyze the installation of chiral amines onto specific keto sugars,pro-ducing bioactive amino sugars.Their activity has been utilized in artificial reactions,such as using the SAT WecE t...Sugar aminotransferases(SATs)catalyze the installation of chiral amines onto specific keto sugars,pro-ducing bioactive amino sugars.Their activity has been utilized in artificial reactions,such as using the SAT WecE to transform valienone into the valuable a-glucosidase inhibitor valienamine.However,the low thermostability and limited activity on non-natural substrates have hindered their applications.Simultaneously improving stability and enzyme activity is particularly challenging owing to the acknowledged inherent trade-off between stability and activity.A customized combinatorial active-site saturation test-iterative saturation mutagenesis(CAST-ISM)strategy was used to simultaneously enhance the stability and activity of WecE toward valienone.Fourteen hotspots related to improving the stability-\activity trade-off were identified based on evolutionary conservation and the average mutation folding energy assessment of 57 residues in the active site of WecE.Positive mutagenesis and combinatorial mutations of these specific residues were accomplished via site-directed saturation mutagenesis(SSM)and iterative evolution cycles.Compared with those of the wild-type(WT)WecE,the quadruple mutant M4(Y321F/K209F/V318R/F319V)displayed a 641.49-fold increase in half-life(t_(1/2))at 40℃ and a 31.37-fold increase in activity toward the non-natural substrate valienone.The tri-ple mutant M3(Y321F/K209F/V318R)demonstrated an 83.04-fold increase in(t_(1/2))at 40℃and a 37.77-fold increase in activity toward valienone.The underlying mechanism was dependent on the strengthened interface interactions and shortened transamination reaction catalytic distance,compared with those of the WT,which improved the stability and activity of the obtained mutants.Thus,we accomplished a general target-oriented strategy for obtaining stable and highly active SATs for artificial amino-sugar biosynthesis applications.展开更多
Improved stereoselective syntheses of the targeted compounds （＋）-valiolamine 1 and （＋）-valienamine 2 starting from naturally abundant （–）-shikimic acid are described. A common key intermediate compound 7 was ...Improved stereoselective syntheses of the targeted compounds （＋）-valiolamine 1 and （＋）-valienamine 2 starting from naturally abundant （–）-shikimic acid are described. A common key intermediate compound 7 was first synthesized from （–）-shikimic acid in 9 steps. The compound 7 was then converted to （＋）-valiolamine 1 in 3 steps, and was also converted to （＋）-valienamine 2 in 4 steps. In summary, （＋）-valiolamine 1 and （＋）-valienamine 2 were synthesized from （–）-shikimic acid in 12 （or 13） steps in 40% and 39% overall yields, respectively.展开更多
With the support by the National Natural Science Foundation of China and the Ministry of Science and Technology of China,the research team led by Prof.Feng Yan(冯雁),collaborating with Prof.Bai LinQuan(白林泉)at the S...With the support by the National Natural Science Foundation of China and the Ministry of Science and Technology of China,the research team led by Prof.Feng Yan(冯雁),collaborating with Prof.Bai LinQuan(白林泉)at the State Key Laboratory of Microbial Metabolism,School of Life Science&Biotechnology,Shanghai Jiao Tong University,recently reported"De novo biosynthesis ofβ-valienamine in engi-展开更多
基金supported by the National Key Research and Development Program of China(2018YFE0200501 and 2020YFA0907700)the National Natural Science Foundation of China(32271306 and 21977067).
文摘Sugar aminotransferases(SATs)catalyze the installation of chiral amines onto specific keto sugars,pro-ducing bioactive amino sugars.Their activity has been utilized in artificial reactions,such as using the SAT WecE to transform valienone into the valuable a-glucosidase inhibitor valienamine.However,the low thermostability and limited activity on non-natural substrates have hindered their applications.Simultaneously improving stability and enzyme activity is particularly challenging owing to the acknowledged inherent trade-off between stability and activity.A customized combinatorial active-site saturation test-iterative saturation mutagenesis(CAST-ISM)strategy was used to simultaneously enhance the stability and activity of WecE toward valienone.Fourteen hotspots related to improving the stability-\activity trade-off were identified based on evolutionary conservation and the average mutation folding energy assessment of 57 residues in the active site of WecE.Positive mutagenesis and combinatorial mutations of these specific residues were accomplished via site-directed saturation mutagenesis(SSM)and iterative evolution cycles.Compared with those of the wild-type(WT)WecE,the quadruple mutant M4(Y321F/K209F/V318R/F319V)displayed a 641.49-fold increase in half-life(t_(1/2))at 40℃ and a 31.37-fold increase in activity toward the non-natural substrate valienone.The tri-ple mutant M3(Y321F/K209F/V318R)demonstrated an 83.04-fold increase in(t_(1/2))at 40℃and a 37.77-fold increase in activity toward valienone.The underlying mechanism was dependent on the strengthened interface interactions and shortened transamination reaction catalytic distance,compared with those of the WT,which improved the stability and activity of the obtained mutants.Thus,we accomplished a general target-oriented strategy for obtaining stable and highly active SATs for artificial amino-sugar biosynthesis applications.
基金We thank the National Natural Science Foundation of China （No. 20972048） for the financial support of this work.
文摘Improved stereoselective syntheses of the targeted compounds （＋）-valiolamine 1 and （＋）-valienamine 2 starting from naturally abundant （–）-shikimic acid are described. A common key intermediate compound 7 was first synthesized from （–）-shikimic acid in 9 steps. The compound 7 was then converted to （＋）-valiolamine 1 in 3 steps, and was also converted to （＋）-valienamine 2 in 4 steps. In summary, （＋）-valiolamine 1 and （＋）-valienamine 2 were synthesized from （–）-shikimic acid in 12 （or 13） steps in 40% and 39% overall yields, respectively.
文摘With the support by the National Natural Science Foundation of China and the Ministry of Science and Technology of China,the research team led by Prof.Feng Yan(冯雁),collaborating with Prof.Bai LinQuan(白林泉)at the State Key Laboratory of Microbial Metabolism,School of Life Science&Biotechnology,Shanghai Jiao Tong University,recently reported"De novo biosynthesis ofβ-valienamine in engi-
