Apramycin is unique in the aminoglycoside family due to its octodiose moiety. However, either the biosynthesis process or the precursors involved are largely unknown. Addition of glycine, as well as serine or threonin...Apramycin is unique in the aminoglycoside family due to its octodiose moiety. However, either the biosynthesis process or the precursors involved are largely unknown. Addition of glycine, as well as serine or threonine, to the Streptomyces tenebrabrius UD2 fermentation medium substantially increases the production of apramycin with little effect on the growth of mycelia, indicating that glycine and/or serine might be involved in the biosynthesis of apramycin. The 13C-NMR analysis of [2-13C] glycine-fed (25% enrichment) apramycin showed that glycine specifically and efficiently incorporated into the only N-CH3 substituent of apramycin on the C7′ of the octodiose moiety. We noticed that the in vivo concentration of S-adenosyl methionine increased in parallel with the addition of glycine, while the addition of methione in the fermentation medium significantly decreased the productivity of apra-mycin. Therefore, the methyl donor function of glycine is proposed to be involved in the methionine cycle but methionine itself was proposed to inhibit the methylation and methyl transfer processes as previously reported for the case of rapamycin. The 15N NMR spectra of [2-13C,15N]serine labeled apramycin indicated that serine may also act as a limiting precursor contributing to the ―NH2 substituents of apramycin.展开更多
Chiral phosphorus ligands have played a crucial role for the recent advances in asymmetric catalysis.This review summarizes chiral phosphorus ligands developed from the Laboratory of Professor Xumu Zhang in the latest...Chiral phosphorus ligands have played a crucial role for the recent advances in asymmetric catalysis.This review summarizes chiral phosphorus ligands developed from the Laboratory of Professor Xumu Zhang in the latest 25 years.A number of iconic phosphorus ligands including bisphosphorus ligands with rigid chiral backbone such as BICP,PennPhos,TunePhos,and f-Binaphane,P-chiral bisphosphorus ligands TangPhos,Binapine,and DuanPhos,phosphine-phosphoramidte ligand YanPhos,noncovalent interaction-assisted ferrocenyl phosphorus ligand ZhaoPhos and WudaPhos,and tridentate ferrocenyl phosphorus ligands f-amphox are introduced,and their applications in asymmetric hydrogenation are emphasized.展开更多
文摘Apramycin is unique in the aminoglycoside family due to its octodiose moiety. However, either the biosynthesis process or the precursors involved are largely unknown. Addition of glycine, as well as serine or threonine, to the Streptomyces tenebrabrius UD2 fermentation medium substantially increases the production of apramycin with little effect on the growth of mycelia, indicating that glycine and/or serine might be involved in the biosynthesis of apramycin. The 13C-NMR analysis of [2-13C] glycine-fed (25% enrichment) apramycin showed that glycine specifically and efficiently incorporated into the only N-CH3 substituent of apramycin on the C7′ of the octodiose moiety. We noticed that the in vivo concentration of S-adenosyl methionine increased in parallel with the addition of glycine, while the addition of methione in the fermentation medium significantly decreased the productivity of apra-mycin. Therefore, the methyl donor function of glycine is proposed to be involved in the methionine cycle but methionine itself was proposed to inhibit the methylation and methyl transfer processes as previously reported for the case of rapamycin. The 15N NMR spectra of [2-13C,15N]serine labeled apramycin indicated that serine may also act as a limiting precursor contributing to the ―NH2 substituents of apramycin.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences XDB20000000,CAS(QYZDY-SSW-SLH029)NSFC(21725205,21432007,21572246)+1 种基金STCSM-18520712200K.C.Wong Education Foundation.
文摘Chiral phosphorus ligands have played a crucial role for the recent advances in asymmetric catalysis.This review summarizes chiral phosphorus ligands developed from the Laboratory of Professor Xumu Zhang in the latest 25 years.A number of iconic phosphorus ligands including bisphosphorus ligands with rigid chiral backbone such as BICP,PennPhos,TunePhos,and f-Binaphane,P-chiral bisphosphorus ligands TangPhos,Binapine,and DuanPhos,phosphine-phosphoramidte ligand YanPhos,noncovalent interaction-assisted ferrocenyl phosphorus ligand ZhaoPhos and WudaPhos,and tridentate ferrocenyl phosphorus ligands f-amphox are introduced,and their applications in asymmetric hydrogenation are emphasized.
