4-hydroxyisoleucine(4-HIL)is a potential drug for diabetes and weight control.4-HIL was produced by expressing ido gene in L-isoleucine(Ile)-producing Corynebacterium glutamicum.But L-lysine(Lys)was also accumulated a...4-hydroxyisoleucine(4-HIL)is a potential drug for diabetes and weight control.4-HIL was produced by expressing ido gene in L-isoleucine(Ile)-producing Corynebacterium glutamicum.But L-lysine(Lys)was also accumulated as the main by-product in this recombinant strain SN02.To attenuate Lys synthesis,two genes in Lys synthetic pathway,i.e.,ddh encoding the diaminopimelic acid dehydrogenase and lysE encoding the specific Lys exporter were deleted in SN02.However,the deletion of ddh increased 4-HIL titer by 28.1%,but did not decrease Lys content;while the deletion of lysE significantly reduced Lys content by 66.7%,but 4-HIL titer also decreased by 19.3%.Therefore,we carried out transcriptome analysis to reveal the global variation in these mutants.Deletion of ddh and lysE(especially lysE)enhanced the transcription of key enzymes in succinylase branch of Lys synthesis pathway(DapD and DapC)and several enzymes involved in succinyl-CoA accessibility(SucC,SucD and OdhI),suggesting the compensatory synthesis of Lys via succinylase branch.In addition,the transcription of ilvBN in Ile synthesis pathway was improved,while the transcription of some genes in the 2-methylcitrate cycle and inositol metabolism pathway was weakened in these mutants.Mere deletion of ddh enhanced the transcription of aceA,ppc and pck,thus promoting oxaloacetate supply and 4-HIL synthesis.Deletion of lysE affected the transcription of some stress-related genes and transporter genes,suggesting that this mutant would be under stress,thus attenuating its 4-HIL synthesis.These findings will be helpful for systematic microbiology and bio-manufacturing of C.glutamicum.展开更多
基金funded by the program of State Key Laboratory of Food Science and Technology(SKLF-ZZA-201904)national first-class discipline program of Light Industry Technology and Engineering(LITE2018-10).
文摘4-hydroxyisoleucine(4-HIL)is a potential drug for diabetes and weight control.4-HIL was produced by expressing ido gene in L-isoleucine(Ile)-producing Corynebacterium glutamicum.But L-lysine(Lys)was also accumulated as the main by-product in this recombinant strain SN02.To attenuate Lys synthesis,two genes in Lys synthetic pathway,i.e.,ddh encoding the diaminopimelic acid dehydrogenase and lysE encoding the specific Lys exporter were deleted in SN02.However,the deletion of ddh increased 4-HIL titer by 28.1%,but did not decrease Lys content;while the deletion of lysE significantly reduced Lys content by 66.7%,but 4-HIL titer also decreased by 19.3%.Therefore,we carried out transcriptome analysis to reveal the global variation in these mutants.Deletion of ddh and lysE(especially lysE)enhanced the transcription of key enzymes in succinylase branch of Lys synthesis pathway(DapD and DapC)and several enzymes involved in succinyl-CoA accessibility(SucC,SucD and OdhI),suggesting the compensatory synthesis of Lys via succinylase branch.In addition,the transcription of ilvBN in Ile synthesis pathway was improved,while the transcription of some genes in the 2-methylcitrate cycle and inositol metabolism pathway was weakened in these mutants.Mere deletion of ddh enhanced the transcription of aceA,ppc and pck,thus promoting oxaloacetate supply and 4-HIL synthesis.Deletion of lysE affected the transcription of some stress-related genes and transporter genes,suggesting that this mutant would be under stress,thus attenuating its 4-HIL synthesis.These findings will be helpful for systematic microbiology and bio-manufacturing of C.glutamicum.
