The anti-tuberculous rifamycins belong to naphthalenic ansamycin based on the structure of aromatic chromophore.Herein,we explored the post-polyketide synthase(PkS)modifications in the biosynthesis of 16-demethyl-rifa...The anti-tuberculous rifamycins belong to naphthalenic ansamycin based on the structure of aromatic chromophore.Herein,we explored the post-polyketide synthase(PkS)modifications in the biosynthesis of 16-demethyl-rifamycins via gene knockout,complementation and in vitro enzyme assays.The collective evidences showed that i)the aromatization of 8-hydroxyl-7,8-dihydronaphtoquinone was accomplished by the combined action of two dehydrogenases,Rifs and Rif;i)the acetylation and methylation of the macrocycle was carried out on naphthoquinone intermediates in preference to naphthol,by Rif-Orf20 and Rif-Orf14,respectively ii)the presence of Rifs/T homologs in ansamycin biosynthetic gene clusters corresponds to the dehydrogenation aromatization mode of dihydronaphthalene.These findings cast new insights into the naphthalene formation and post-PkS modification of ansamycins.展开更多
Over-expression of the pathway specific positive regulator gene is an effective way to activate silent gene cluster.In the curret study,the SARP family regulatory gene,vasR2,was over-expressed in strain Verrucosispora...Over-expression of the pathway specific positive regulator gene is an effective way to activate silent gene cluster.In the curret study,the SARP family regulatory gene,vasR2,was over-expressed in strain Verrucosispora sp.NS0172 and the cryptic gene cluster responsible for the biosynthesis of pentaketide ansamycin was partially activated.Two tetraketides(1 and 2)and a triketide(3)ansamycins,together with five known compounds(4–8),were isolated and elucidated from strain NS0172OEvasR2.Their NMR data were completely assigned by analysis of their HR-ESI-MS and 1H,13C NMR,HMQC,HMBC and 1H-1H COSY spectra.展开更多
基金We thank the financial support from the National Natural Science Foundation of China(22137009 and 21907067).
文摘The anti-tuberculous rifamycins belong to naphthalenic ansamycin based on the structure of aromatic chromophore.Herein,we explored the post-polyketide synthase(PkS)modifications in the biosynthesis of 16-demethyl-rifamycins via gene knockout,complementation and in vitro enzyme assays.The collective evidences showed that i)the aromatization of 8-hydroxyl-7,8-dihydronaphtoquinone was accomplished by the combined action of two dehydrogenases,Rifs and Rif;i)the acetylation and methylation of the macrocycle was carried out on naphthoquinone intermediates in preference to naphthol,by Rif-Orf20 and Rif-Orf14,respectively ii)the presence of Rifs/T homologs in ansamycin biosynthetic gene clusters corresponds to the dehydrogenation aromatization mode of dihydronaphthalene.These findings cast new insights into the naphthalene formation and post-PkS modification of ansamycins.
基金supported by the National Natural Science Foundation of China(Nos.81673317,81530091,and 31570039)the Open Funding Project of State Key Laboratory of Microbial Metabolite Funding(No.MMLKF17-09)the Program for Changjiang Scholars and Innovative Research Team in University(No.IRT_17R68).
文摘Over-expression of the pathway specific positive regulator gene is an effective way to activate silent gene cluster.In the curret study,the SARP family regulatory gene,vasR2,was over-expressed in strain Verrucosispora sp.NS0172 and the cryptic gene cluster responsible for the biosynthesis of pentaketide ansamycin was partially activated.Two tetraketides(1 and 2)and a triketide(3)ansamycins,together with five known compounds(4–8),were isolated and elucidated from strain NS0172OEvasR2.Their NMR data were completely assigned by analysis of their HR-ESI-MS and 1H,13C NMR,HMQC,HMBC and 1H-1H COSY spectra.
