Discovery of pentaene polyols by the activation of an enediyne gene cluster: biosynthetic implications for 9-membered enediyne core structures

The identification and characterization of enediyne polyketide synthases (PKSEs) revealed that PKSE-bound polyene is a common intermediate, while its subsequent tailoring steps to enediyne cores remain obscure. Herein, we report pentaene polyols 5-7 and cinnamic acid derivatives 8 and 9 biosynthesized from an activated enediyne biosynthetic gene cluster in Streptomyces sp. CB02130. The C-1027 pksE could partially complement production of these polyene polyols in a CB02130 mutant where the native pksE is inactivated. The yields of 5-7 were improved by increasing the cellular pool of l -Phe through either gene inactivation of a prephenate dehydrogenase WlsPDH or supplementation of l -Phe. A flexible ammonia lyase WlsC4 is responsible for biosynthesis of 8 and 9 from l -Phe. The co-localization of wls PDH and PKSE gene cassette supports their close evolutionary relationships and an enediyne genome mining strategy using WlsPDH. These findings not only provide a facile approach to activate silent enediyne BGCs, but suggest that a polyene epoxide intermediate may be formed for construction of 9-membered enediyne macrocycles. Production of three new pentaene polyols 5-7 by an activated enediyne gene cluster and their biosynthetic study suggest the presence of a polyene epoxide intermediate during the early steps of 9-membered enediyne core formation.