Cloning, heterologous expression, and characterization of the gene cluster required for gougerotin biosynthesis

Gougerotin, a peptidyl nucleoside antibiotic, possesses antitumor, antiviral, antibacterial, antimycoplasma, anthelmintic, and acaricidal activities. Here, we report the cloning of a complete gougerotin biosynthetic gene cluster from Streptomyces graminearus and heterologous production of gougerotin in Streptomyces coelicolor. Sequence analysis of a 28.7 kb DNA fragment indicated that the cluster consists of 25 open reading frames (ORFs). Gene disruption and genetic complementation experiments revealed that 15 of the 25 ORFs are required for gougerotin biosynthesis. A gougerotin biosynthetic pathway was proposed based on the analyses of bioinformatics and intermediates accumulated in selected gene inactivation mutants. These studies substantially promoted our understanding of gougerotin biosynthesis and provide "building blocks" for combinatorial biosynthesis using genes encoding different enzymes in nucleoside antibiotics.