A novel luminescent double-interpenetrated metal-organic framework(MOF),named{[In_(6)(O)_(3)(BTB)_(4)]·3H_(2)O}_(n)(1),is designed and synthesized using the tritopic linkers(1,3,5-tris(4-carboxyphenyl)benzene(H_(...A novel luminescent double-interpenetrated metal-organic framework(MOF),named{[In_(6)(O)_(3)(BTB)_(4)]·3H_(2)O}_(n)(1),is designed and synthesized using the tritopic linkers(1,3,5-tris(4-carboxyphenyl)benzene(H_(3)BTB))and tetranuclear clusters[In_(4)O_(2)(COO)_(8)].1 features 3,8-connected dual-wall"cage-in-cage"and exhibits excellent chemical stability owing to its high connectivity and double-interpenetrated architectures.Moreover,it could rapidly detect thiamphenicol(THI),nitrofurazone(NFZ),and nitrofurantoin(NFT)antibiotics in N,N-dime-thylformamide(DMF)with superior detection sensitivity(Ksv)and low detection limits(LOD)of 4.52×10^(3)M^(-1)and 348.6 ppm,1.43×10^(5)M^(-1)and 13.8 ppm,and 1.47×10^(5)M^(-1)and 12.1 ppm for THI,NFZ,and NFT,respectively.Additionally,compound 1 exhibits good selectivity and recyclability.It is also effectively used to detect NFT in the milk sample.Furthermore,the mechanism of luminescence quenching was revealed through the experimental results and the density functional theory calculations.The occurrence of photo-induced electron transfer(PET)affects the fluorescence quenching effect of NFT and NFZ.The design of indium-based MOFs has the potential to detect antibiotic residues in food.展开更多
Summary of main observation and conclusion The radical S-adenosylmethionine(SAM)aminomutases represent an important pathway for the biosynthesis of p-amino acids.In this study,we report biochemical characterization of...Summary of main observation and conclusion The radical S-adenosylmethionine(SAM)aminomutases represent an important pathway for the biosynthesis of p-amino acids.In this study,we report biochemical characterization of BlsG involved in blasticidin S biosynthesis as a radical SAM arginine 2,3-aminomutase.We showed that BlsG acts on both£-arginine and L-lysine with comparable catalytic efficiencies.Similar dual substrate specificity was also observed for the lysine 2,3-aminomutase from Escherichia coli(LAMec).The catalytic efficiency of LAMEc is similar to that of BlsG,but is significantly lower than that of the enzyme from Clostridium subterminale(LAMcs),which acts only on L-lysine rather than on L-arginine.Moreover,we showed that enzymes can be grouped into two major phylogenetic clades,each corresponding to a certain C3 stereochemistry of the P-amino acid product.Our study expands the radical SAM aminomutase members and provides insights into enzyme evolution,supporting a trade-off between substrate promiscuity and catalytic efficiency.展开更多
基金supported by the National Science Foundation of China(21601115 and 22275118).
文摘A novel luminescent double-interpenetrated metal-organic framework(MOF),named{[In_(6)(O)_(3)(BTB)_(4)]·3H_(2)O}_(n)(1),is designed and synthesized using the tritopic linkers(1,3,5-tris(4-carboxyphenyl)benzene(H_(3)BTB))and tetranuclear clusters[In_(4)O_(2)(COO)_(8)].1 features 3,8-connected dual-wall"cage-in-cage"and exhibits excellent chemical stability owing to its high connectivity and double-interpenetrated architectures.Moreover,it could rapidly detect thiamphenicol(THI),nitrofurazone(NFZ),and nitrofurantoin(NFT)antibiotics in N,N-dime-thylformamide(DMF)with superior detection sensitivity(Ksv)and low detection limits(LOD)of 4.52×10^(3)M^(-1)and 348.6 ppm,1.43×10^(5)M^(-1)and 13.8 ppm,and 1.47×10^(5)M^(-1)and 12.1 ppm for THI,NFZ,and NFT,respectively.Additionally,compound 1 exhibits good selectivity and recyclability.It is also effectively used to detect NFT in the milk sample.Furthermore,the mechanism of luminescence quenching was revealed through the experimental results and the density functional theory calculations.The occurrence of photo-induced electron transfer(PET)affects the fluorescence quenching effect of NFT and NFZ.The design of indium-based MOFs has the potential to detect antibiotic residues in food.
基金This work is supported in part by grants from the National Natural Science Foundation of China(Nos.21822703,31670060,and 21921003)from the National Key Research and Development Program(2018Y F A0900402 and 2016 Y F A0501302).
文摘Summary of main observation and conclusion The radical S-adenosylmethionine(SAM)aminomutases represent an important pathway for the biosynthesis of p-amino acids.In this study,we report biochemical characterization of BlsG involved in blasticidin S biosynthesis as a radical SAM arginine 2,3-aminomutase.We showed that BlsG acts on both£-arginine and L-lysine with comparable catalytic efficiencies.Similar dual substrate specificity was also observed for the lysine 2,3-aminomutase from Escherichia coli(LAMec).The catalytic efficiency of LAMEc is similar to that of BlsG,but is significantly lower than that of the enzyme from Clostridium subterminale(LAMcs),which acts only on L-lysine rather than on L-arginine.Moreover,we showed that enzymes can be grouped into two major phylogenetic clades,each corresponding to a certain C3 stereochemistry of the P-amino acid product.Our study expands the radical SAM aminomutase members and provides insights into enzyme evolution,supporting a trade-off between substrate promiscuity and catalytic efficiency.
