High Plasticity of the Amicetin Biosynthetic Pathway in Streptomyces sp. SHP 22-7 Led to the Discovery of Streptcytosine P and Cytosaminomycins F and G and Facilitated the Production of 12F-Plicacetin

A chemical reinvestigation of the Indonesian strain Streptomycessp. SHP 22-7 led to the isolation of three newpyrimidine nucleosides, along with six known analogues and zincphyrin. The structures of the new compounds (6,7,10) were elucidated by employing spectroscopic techniques (NMR, MS,CD, and IR) as well as enantioselective analyses of methyl branched side chain configurations. Application of the precursor-directed feeding approach led to the production and partial isolation of nine further pyrimidine analogues. The newcompounds6,7, and11and three of the known compounds(2-4) were found to possess antimycobacterial and cytotoxic properties.