Production of Diketopiperazine Derivatives by Pathway Engineering with Different Cyclodipeptide Synthases from Various Streptomyces Strains

Cyclodipeptides from fungi and bacteria are often modifiedby differenttailoring enzymes. They display various biological and pharmacologicalactivities, and some derivatives are used as drugs. In a previousstudy, we elucidated the function of the silent guatrypmethine genecluster from Streptomyces cinnamoneus containinga cyclodipeptide synthase (CDPS) core gene gtmA andfour genes gtmB-gtmE for tailoring enzymes.The latter are used in this study for the design of modified cyclodipeptidesby genetic engineering. Addition of six different cyclodipeptidesto the Streptomyces albus transformant harboring gtmB-gtmE led to the detection of different pathwayproducts. Coexpression of five CDPS genes from four Streptomyces strains with gtmB-gtmE resulted in the formationof diketopiperazine derivatives, differing in their modification stages.Our results demonstrate the potential of rational gene combinationto increase structural diversity.

Automated summary

Cyclodipeptides from fungi and bacteria, which are often modified by different tailoring enzymes, have various biological and pharmacological activities. In this study, we used genetic engineering to design modified cyclodipeptides by incorporating gtmA core gene and gtmB-gtmE genes from the silent guatrypmethine gene cluster of Streptomyces cinnamoneus. Addition of different cyclodipeptides to the transformant led to the detection of diverse pathway products. Coexpression of CDPS genes from multiple Streptomyces strains with gtmB-gtmE resulted in the formation of diketopiperazine derivatives with varying modification stages. Our results demonstrate the potential of rational gene combination to increase structural diversity.