Microorganisms release small volatile metabolites with unique structures, e. g. the polymethylated homosesquiterpene sodorifen from Serratia plymuthica . Two unusual enzymes with novel features are involved in its biosynthesis, a C -methyltransferase with cyclization activity and a terpene synthase that accepts a non-canonical monocyclic C 16 substrate. The novel class of methyltransferases represents an alternative route that...