Natural cyclohexapeptide AFN A1 from Streptomyces alboflavus 313 has moderate antibacterial and antitumor activit-ies.An artificial designed AFN A1 homodimer,di-AFN A1,is an antibiotic exhibiting 10 to 150 fold higher biological activities,com-pared with the monomer.Unfortunately,the yield of di-AFN A1 is very low(0.09±0.03 mg·L-1)in the engineered strain Streptomy-ces alboflavus 313_hmtS(S.albo/313_hmtS),which is not friendly to be genetically engineered for titer improvement of di-AFN A1 production.In this study,we constructed a biosynthetic gene cluster for di-AFN A1 and increased its production through heterologous expression.During the collection of di-AFN A1 biosynthetic genes,the afn genes were located at three sites of S.alboflavus 313 gen-ome.The di-AFN A1 biosynthetic gene cluster(BGC)was first assembled on one plasmid and introduced into the model strain Strepto-myces lividans TK24,which produced di-AFN A1 at a titer of 0.43±0.01 mg·L-1.To further increase the yield of di-AFN A1,the di-AFN A1 BGC was multiplied and split to mimic the natural afn biosynthetic genes,and the production of di-AFN A1 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 A1 in-creased 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 A1 with a remarkable increased titer will greatly facilitate the following synthetic biological study and drug development of this dimeric cyclohexapeptide.

WEI Weijia;WANG Wenzhao;LI Chao;TANG Yue;GUO Zhengyan;CHEN Yihua

State Key Laboratory of Microbial Resources,Institute of Microbiology,Chinese Academy of Sciences,Beijing 100101,China;College of Life Sciences,University of Chinese Academy of Sciences,Beijing 100149,China;Institute of Medicinal Biotechnology,Chinese Academy of Medical Sciences,Beijing 100050,China

中国天然药物

[1]WEI Weijia;WANG Wenzhao;LI Chao;TANG Yue;GUO Zhengyan;CHEN Yihua-.Construction and heterologous expression of the di-AFN A1 biosynthetic gene cluster in Streptomyces model strains)[J].中国天然药物,2022(11):873-880

cyclohexapeptide,alboflavus,activit,homodimer,hmtS,albo,afn,lividans,TK24

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