Figure 6

Proposal for the AdpA-mediated regulation of Lcm and the landomycin A biosynthetic pathways in S. cyanogenus. Both biosynthetic pathways compete for PKS precursor supply. AdpA, presumably through direct binding to the lcmRIII promoter region, activates the expression of this lcm cluster-situated transcriptional regulator. Both LcmRII and LcmRIII are positive regulators of Lcm production. The role of LcmRI in the regulation of the Lcm biosynthesis is unclear and awaits further investigations.