Roquefortine/meleagrin biosynthetic gene cluster and proposed corresponding pathway.
A, organization of the roquefortine/meleagrin biosynthetic gene cluster. B, proposed roquefortine/meleagrin pathway. Numbers between brackets are compound identifiers used throughout this study. Enzymatic catalyzed reactions are indicated by solid arrows, whereas chemical reactions are indicated by dashed arrows. Structures shown in brackets could not be detected, whereas gray reactions and compounds were previously proposed for various Penicillium species (6, 8, 10).