Common biosynthetic feature of fortimicin-group antibiotics

The fortimicin (FTM) group antibiotics are produced by actinomycetes belonging to various genera. FTM's and sannamycins are the products of Micromonospora olivasterospora and Streptomyces sannanensis, respectively. The possible presence of common features of the biosynthesis of these structurally related antibiotics in the two producers was examined. Enzymatic studies were done by the bioconversion experiments using FTM precursors and the washed cells of S. sannanensis. Ion pair/reverse-phase HPLC was employed as the analytical tool. S. sannanensis could convert almost all FTM precursors to the expected structures in the down stream of the pathway except one step. Thus the sets of the biosynthetic enzymes of the two bacteria share the common substrate specificity and react alternatively.