Natural cyclohexapeptide AFN A_(1) from Streptomyces alboflavus 313 has moderate antibacterial and antitumor activities.An artificial designed AFN A_(1) homodimer,di-AFN A_(1),is an antibiotic exhibiting 10 to 150 fol...Natural cyclohexapeptide AFN A_(1) from Streptomyces alboflavus 313 has moderate antibacterial and antitumor activities.An artificial designed AFN A_(1) homodimer,di-AFN A_(1),is an antibiotic exhibiting 10 to 150 fold higher biological activities,compared with the monomer.Unfortunately,the yield of di-AFN A_(1) is very low(0.09±0.03 mg·L^(−1))in the engineered strain Streptomyces alboflavus 313_hmtS(S.albo/313_hmtS),which is not friendly to be genetically engineered for titer improvement of di-AFN A_(1) production.In this study,we constructed a biosynthetic gene cluster for di-AFN A_(1) and increased its production through heterologous expression.During the collection of di-AFN A_(1) biosynthetic genes,the afn genes were located at three sites of S.alboflavus 313 genome.The di-AFN A_(1) biosynthetic gene cluster(BGC)was first assembled on one plasmid and introduced into the model strain Streptomyces lividans TK24,which produced di-AFN A_(1) at a titer of 0.43±0.01 mg·L^(−1).To further increase the yield of di-AFN A_(1),the di-AFN A_(1) BGC was multiplied and split to mimic the natural afn biosynthetic genes,and the production of di-AFN A_(1) increased to 0.62±0.11 mg·L^(−1) in S.lividans TK24 by the later strategy.Finally,different Streptomyces hosts were tested and the titer of di-AFN A_(1) increased to 0.81±0.17 mg·L^(−1),about 8.0-fold higher than that in S.albo/313_hmtS.Successful heterologous expression of di-AFN A_(1) with a remarkable increased titer will greatly facilitate the following synthetic biological study and drug development of this dimeric cyclohexapeptide.展开更多
基金supported by the Ministry of Science and Technology of the People’s Republic of China(No.2020YFA0907703)the National Natural Science Foundation of China(Nos.32070044,32025002)the Biological Resources Programme,Chinese Academy of Sciences(No.KFJ-BRP-009)。
文摘Natural cyclohexapeptide AFN A_(1) from Streptomyces alboflavus 313 has moderate antibacterial and antitumor activities.An artificial designed AFN A_(1) homodimer,di-AFN A_(1),is an antibiotic exhibiting 10 to 150 fold higher biological activities,compared with the monomer.Unfortunately,the yield of di-AFN A_(1) is very low(0.09±0.03 mg·L^(−1))in the engineered strain Streptomyces alboflavus 313_hmtS(S.albo/313_hmtS),which is not friendly to be genetically engineered for titer improvement of di-AFN A_(1) production.In this study,we constructed a biosynthetic gene cluster for di-AFN A_(1) and increased its production through heterologous expression.During the collection of di-AFN A_(1) biosynthetic genes,the afn genes were located at three sites of S.alboflavus 313 genome.The di-AFN A_(1) biosynthetic gene cluster(BGC)was first assembled on one plasmid and introduced into the model strain Streptomyces lividans TK24,which produced di-AFN A_(1) at a titer of 0.43±0.01 mg·L^(−1).To further increase the yield of di-AFN A_(1),the di-AFN A_(1) BGC was multiplied and split to mimic the natural afn biosynthetic genes,and the production of di-AFN A_(1) increased to 0.62±0.11 mg·L^(−1) in S.lividans TK24 by the later strategy.Finally,different Streptomyces hosts were tested and the titer of di-AFN A_(1) increased to 0.81±0.17 mg·L^(−1),about 8.0-fold higher than that in S.albo/313_hmtS.Successful heterologous expression of di-AFN A_(1) with a remarkable increased titer will greatly facilitate the following synthetic biological study and drug development of this dimeric cyclohexapeptide.
